Battle at the Helvault

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — For each player, exile up to one target non-Saga, nonland permanent that player controls until Battle at the Helvault leaves the battlefield.
III — Create Avacyn, a legendary 8/8 white Angel creature token with flying, vigilance, and indestructible.