This elegant loop turns the back-and-forth cycle of Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight into a relentless sacrifice engine, leveraging Isilu's granted persist to bring back Ambitious Aetherborn every time it hits the graveyard. Viscera Seer acts as the clean outlet that endlessly sacrifices the Aetherborn while stacking up your library with its scry ability. The real magic happens when Ambitious Aetherborn re-enters the battlefield: its fabricate 1 ability triggers to place a +1/+1 counter on it, which immediately neutralizes the -1/+1 counter from persist via state-based actions. This leaves the Aetherborn completely fresh and ready to be sacrificed to Viscera Seer all over again, fueling an infinite storm of death triggers.