Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.
{T}: Add {R}. If that mana is spent on a Dragon creature spell, it gains haste until end of turn.
({T}: Add {G}.)
Sacrifice Seal of Doom: Destroy target nonblack creature. It can't be regenerated.
Flash When Omen of the Forge enters, it deals 2 damage to any target. {2}{R}, Sacrifice Omen of the Forge: Scry 2.
({T}: Add {B}, {R}, or {G}.) Ziatora's Proving Ground enters tapped. Cycling {3} ({3}, Discard this card: Draw a card.)
(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Each opponent sacrifices a creature or planeswalker of their choice. II — Each opponent discards a card. III — Put target creature or planeswalker card from a graveyard onto the battlefield under your control.
{1}, Sacrifice Cankerbloom: Choose one — • Destroy target artifact. • Destroy target enchantment. • Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)