At the beginning of your end step, exile target creature you control, then return it to the battlefield under its owner's control. Then if it's the first end step of the turn, there is an additional end step after this step.
Y'shtola turns your end step into a blink engine—each turn you get two end steps, exiling and returning a creature to retrigger enter-the-battlefield effects twice. Build a mono-blue value engine loaded with ETB creatures (card draw, bounce, counters, mill, tutors), grind out advantage every turn, and snowball into a dominating board or a combo. You play a controlling early game, deploy a few key value creatures, then let the doubled end steps bury opponents in incremental advantage.
Free, repeatable double blink every turn for ETB value without spending mana
Resets summoning sickness and protects a creature from sorcery-speed removal at end step
Mono-blue gives access to the best card draw, counterspells, and tutors in the format
Enables hard combos with ETB creatures (e.g. infinite untaps, mill, or bounce loops)
Painfully slow without ETB payloads—she does nothing on her own
Mono-color limits removal and ramp diversity
Relies on creatures sticking; sweepers and spot removal on Y'shtola gut the engine
High commander cost (6 mana) and easy to disrupt before she gets going
Legendary Creature — Cat Druid
