The Curse of Fenric [Doctor Who]

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — For each player, destroy up to one target creature that player controls. For each creature destroyed this way, its controller creates a 3/3 green Mutant creature token with deathtouch.
II — Target nontoken creature becomes a 6/6 legendary Horror creature named Fenric and loses all abilities.
III — Target Mutant fights another target creature named Fenric.