Welcome to the Archfiend Guide - the one-stop shop for all you need to pilot this collection of ferocious fiends. If you want a deck with an incredible grind game, enjoy archetypes with multiple viable ways to build the deck, or just want the chance to use Yugi's iconic monster Loading..., you're in the right place.
DISCLAIMER: I am not including every card with the word 'Archfiend' in its name within this guide, and instead intend to focus on the support and synergies relevant to the recently released Ritual strategy.
SECOND DISCLAIMER: At present, this deck's primary win condition is war crimes. Access to nearly any Fiend in the game gives us numerous ways to turnskip, floodgate, or lock the opponent out of playing the game completely. You can opt not to play this way, but from a competitive viewpoint the deck WILL be weaker - there is simply no way for fair and fun gameplay to compete with ripping the opponent's entire hand, locking them from using any spells or traps for 2 turns, or negating all graveyard effects or quick-play spells for just the opponent.
Strengths:
Our gameplay is non-linear and can very easily adapt to unusual hands or opponent endboards
We can play going first or second thanks to the power of Loading... and have enough gas to both push through handtraps and break boards
With access to nearly every Fiend in the game and multiple different viable builds, you can customize Archfiends to the style of Yu-Gi-Oh you prefer to play
There are few decks with a better grind game than Archfiend, if you can simplify the gamestate you will win far more often than not
Weaknesses:
Loading... is a severe chokepoint for the deck unless you already have a critical mass of Archfiend cards in hand
Both Loading... and Loading... apply an extremely restricting lock on summoning ANY monsters from the extra deck aside from 'Archfiend' cards, requiring careful play
We're a graveyard deck, sometimes the opponent has Loading... or Loading... and the only play is to go next
Core
Engines
Tech Choices
Decklists
Our Royalty
Archfiend Emperor
Our boss monster in nearly every variant of the deck. Emperor is equally strong when going first or second between the boardwipe when summoned and the effect to special summon any Fiend from the deck, gy, or banishment. Being unaffected by ANY other monster effects, including your own, allows for you to pull off some silly stuff like one-sided Loading... boardclears or sending your opponent's entire hand to the graveyard with Loading... and leaving them to out it + ideally Loading... or Loading... with a single card.
Archfiend Matriarch
Primarily played in 'Pure' variants of the deck with a higher Archfiend Spell / Trap line-up, Matriarch shines in the grind game as a way to continually recycle copies of Loading... or whichever Archfiend traps you decide on. Being a LIGHT Fiend, unlike Emperor, also allows you to ritual summon her to wipe opponent backrow before going into the Fiendsmith line or search her with Loading....
Matador Archfiend
Most at home in variants running Loading..., Matador can be somewhat awkward to play given that Loading... is not an Archfiend card and therefor cannot be searched from deck with in-archetype cards. The combo potential offered by pairing it with Loading..., however, is substantial and allows the chance to use both ritual and fusion effects in one trigger for absurd value in addition to Matador searching 2 cards. This is one of the best ways to create tribute fodder if running Loading....
The Royal Retinue
Royal Archfiend
One of our best starters and extenders... as well as our worst self-imposed lock. Always save Royal Archfiend for once you've finished with your Extra Deck plays for the turn, as the extremely limited Archfiend monsters available after it are not worth playing. Keep in mind that it can use its effect from the field as well as the hand.
Duke Archfiend
An awkwardly designed card that is only made worth using by the powerful effect of Loading..., Duke is used to send Loading... to the graveyard and increase its level enough to serve as one-card ritual material. Don't run it unless you're playing a list with Usurpation and an archfiend trap package.
Shipping Archfiend
This card is only useful in combination with Loading... as a way to set-up Loading... at the start of your opponent's turn. The only reason to do this is if you already have Storm and don't want to spend dust crafting a different Fiend engine to use with Emperor.
Highness Archfiend
Sharing the same lock as Loading..., Highness is the card you search with Royal and only use after your extra deck plays for the turn are exhausted. However, being a LIGHT Fiend, it can enable the Fiendsmith line so long as you do not activate its normal summon effect. It can be shuffled back into the deck later by most of the Fiendsmith cards.
Archfiend Heiress
Run at one copy in every nearly every Archfiend list that you'll encounter, Heiress is an incredible searcher given the vast number of cards that contain Archfiend within their names. Keep in mind that you cannot discard it as a cost to trigger her, it must be as part of a card effect like Loading....
Archfiend Eccentrick
Not worth running the vast majority of the time, but can theoretically find its way into Fiendsmith variants of the deck as a meta-call against heavy backrow strategies or an extra answer to Loading... that can be searched with Loading....
Regal Raiment
Archfiend Strategy
Strategy is a great field spell for us, so long as you remember that the 1000 ATK boost applies to Both players. Despite being pseudo-towers, neither Emperor nor Matriarch have very impressive stats on their own without Strategy on field. Aside from that, Strategy is an amazing searcher for the versatility of finding any archfiend card. Just don't banish your cost for Loading....
Archfiend's Usurpation
An incredible card that is only limited by the unfortunate line of text "You can only activate 1 "Archfiend's Usurpation" per turn." on it. This card is a starter via Loading..., removal via Loading..., an extra ritual spell, and even a way to boardwipe on the opponent's turn by ritual summoning either one of our boss monsters.
Archfiend Playtime
In more 'Pure' variants of the deck with a higher in-archetype Archfiend count, pulling this card off with an Archfiend in extra before extra deck locking yourself makes it feel like a custom card. 3 bodies for link summoning, one of which sends Loading... for another search is absurd. It can also be used to start Fiendsmith plays by summoning Loading... pre-lock.
Throne of the Archfiends
As far as archetypal ritual spells go, this one is pretty good. Listed on both Emperor and Matriarch for synergy with Loading..., can ritual summon from everywhere but the deck, and recycles itself during each standby phase. The one thing to remember is that it only recycles if Emperor is in the extra deck, not Matriarch, so plan accordingly if you need discard fodder.
Archfiend's Ghastly Glitch
While not technically designed as support for Archfiends, this card is good enough to be considered an honorary member of the archetype and should be run in any variant of the deck using Loading... and a trap line-up. Removal to break boards, a way to tutor our best fiends to the gy, and a way to dodge targeted negation effects.
Archfiend's Fervor
Fervor is... an odd one. It seems very useful on paper - being able to banish it as a starter as well as use it as an endboard piece. In practice though, even in pure Archfiend lists its usually one of the first cards I cut when I start tinkering. Your mileage may vary.
Fiendsmith
Fiendsmith is, for obvious reasons, our best choice of supplemental engines.
Fiendsmith combo naturally goes into Loading..., which serves as an Archfiend starter via Loading...
Fiendsmith allows us to run just one copy of Loading... by recycling it - you don't want to see it without another Archfiend starter first
Fiendsmith gives us the gas needed to break boards and easy access to one of our best endboard pieces in Loading...
Don't Cut Loading...!! The card is far better than you think and allows you to play around bricks in hand while saving normal summon and still accessing full Fiendsmith line
Loading... + any awkward card in hand (Rhino, Heiress, an Archfiend trap that you need in gy to set with Loading..., etc)
Search Loading... instead of Loading..., discard the brick (trigger if Buio, Heiress, Rhino, etc)
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
In any variant running it, Tour Guide is your favorite opener.
If you have access to Fiendsmith cards, try to bait out interaction with them first before committing your normal summon
Remember that Loading... is a Lv3 LIGHT Fiend. With an extender like Buio in hand, you can go > Highness > Requiem > Fiendsmith line > Buio target Tour Guide to extend if interrupted
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Buio is good enough that I very nearly included it in the 'Core' section and every single one of my current lists on Master Duel run it. It facilitates our grind game, works as both starter and extender, shares an attribute with Loading... to work as Loading... material, and the art for Buio, Mutiny, and Luce goes crazy hard. What more could we want?
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Unfortunately, our G.O.A.T. is stuck on the sidelines until his upcoming support cards are released. When Loading... and Loading... come to Master Duel we'll be so back, but until then you're better off avoiding this low-to-the-ground, control style variant of the deck.
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
One of this deck's greatest strengths is the sheer variety of powerful Fiend monsters that have been released down the years... but that variety comes with plenty of options to choose from. I highly recommend keeping the few slots reserved for these cards fluid and adjust your deckbuilding to match the meta you're playing against.
Best In Slot
As mentioned in the disclaimer, our deck's most consistent win condition is to commit the kinds of war crimes that banlists are named after. In the current meta, handtraps are being sidelined by many deck for powerful turn-neutral quick-play spells like Loading..., Loading..., Loading..., or Loading.... This allows us to often win the game as simply as winning the coin toss, as most decks cannot recover from 0 cards in hand. This also enables us to entirely ignore cards like Maxx "C" or the Mulcharmies, as resolving this effect will send all the drawn cards to the grave regardless.
Loading... fusion summon Loading..., FUSION MATERIAL MATTERS! If you have access to an extra body, shuffle back an Engraver + Lurrie to leave Lacrima and Requiem in grave to send Loading... to the grave during the opponent's turn. If you do not, shuffle back Lurrie + Lacrima
Without another body, link summon into Loading... and special summon Loading... from the grave by banishing both copies of Engraver. With another body, summon it now instead of Agnumday. Either way, get enough material for a Link 4
Summon Loading... and search any combination of cards that puts Loading... in the extra deck with a ritual spell in hand. In this example, Loading... and Loading...
Loading...'s 2nd effect to put Emperor in the extra deck
Loading...'s effect to special summon Loading..., giving you enough ritual material and clearing the EMZ
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Despite being arguably a better lock than Norleras due to lingering for multiple turns and preventing decks like Sky Striker from simply topdecking Engage with a now-full grave, it's also harder to use. Even with our deck gaining an extra normal summon courtesy of Loading..., needing to special summon Loading... first and search out Loading... to normal summon rather than just sending a card to grave and banishing it is difficult.
Make sure you track your normal summons and either save one or make Loading... during the tail-end of your combo to keep around until he can use his effect
Summon Engraver shuffling Moon then link into Loading...
Sequence shuffle Rhino and Heiress to summon Loading...
Usurpation set Loading... use it to summon Loading... (depending on your hand here, the next step could also be to Link summon Loading... if you have a discard to clear the EMZ as well as extra monsters in hand as ritual fodder)
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If committing war crimes sounds unappealing, Regenesis is the correct tech choice given its synergies with the deck. The downside is that a single negate is often not enough in the current metagame, and you will need more endboard pieces to avoid being blown up immediately.
Loading... is directly searchable using in-archetype cards given the 'Archfiend' in its name
After using the effect of Loading..., it is a high enough level to serve as ritual material with a set Loading... for a boardwipe via Loading... during the opponent's turn
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chromium Browsers For Chromium browsers (Chrome/Edge/Opera/Brave...etc) just click "Add to chrome" on the store page and it'll work on most if not all chromium browsers. After using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the DevTools window => Navigate to the Console tab in the window => Paste the export code => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code, then if you're on mobile look for the *globe* icon and tap on it to run the code (Chrome only), for PC users just hit enter.
The deck will save automatically
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
