Chainer's Torment

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Chainer's Torment deals 2 damage to each opponent and you gain 2 life.
III — Create an X/X black Nightmare Horror creature token, where X is half your life total, rounded up. It deals X damage to you.

Narci, Fable Singer

Lifelink
Whenever you sacrifice an enchantment, draw a card.
Whenever the final chapter ability of a Saga you control resolves, each opponent loses X life and you gain X life, where X is that Saga's mana value.

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.