Whenever Ydwen Efreet blocks, flip a coin. If you lose the flip, remove Ydwen Efreet from combat and it can't block this turn. Creatures it was blocking that had become blocked by only Ydwen Efreet this combat become unblocked.
Read ahead I — Create a 0/2 colorless Thopter artifact creature token with flying named Ornithopter. II — Tap any number of untapped artifacts you control. When you do, Yotia Declares War deals that much damage to target creature or planeswalker. III — Up to one target artifact you control becomes an artifact creature with base power and toughness 4/4 until end of turn.