Mairsil, the Pretender + Blood Vassal + Endling + Devoted Druid

Mairsil, the Pretender

Blood Vassal

Endling

Devoted Druid

How it works

1. Activate Mairsil using Endling's third ability by paying , giving Mairsil undying until end of turn.
2. Activate Mairsil using Blood Vassal's ability by sacrificing it, adding .
3. Mairsil dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
4. Activate Mairsil using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
5. Repeat.

Mairsil, the Pretender acts as the ultimate receptacle for this sinister alchemy, absorbing the activated abilities of every exiled card in your possession to unlock a self-sustaining loop. By caging Blood Vassal, Mairsil gains the ability to sacrifice itself for black mana, while Devoted Druid provides the crucial untap mechanic by placing a -1/-1 counter on Mairsil—which conveniently cancels out any +1/+1 counters it accumulates. Meanwhile, Endling provides the essential safety net with its undying ability, ensuring that every time Mairsil perishes from its sacrifices, it immediately rises from the grave ready to continue churning out infinite black mana and endless death triggers.