Check for bystials and izuna when activating maiden from hand. Jump to ultimate spirit if opponent activates a bystial. You can negate lupis summoning from GY with spirit dragon or negate izuna dumping lupis to GY with ultimate spirit. If hit with a nibiru before summoning sifr, you can still end on 1 spirit dragon with synchro rumble. Tyrant dragon in GY for follow up in case the board gets super poly-ed. Spirit dragon can jump into the second ultimate dragon and when it gets destroyed at the end phase, you can special summon tyrant dragon from GY with ultimate spirit effect.