Requires

Nim Deathmantle must be on the battlefield. Ashnod's Altar must be on the battlefield. Xorn must be on the battlefield. Brazen Freebooter must be on the battlefield. Mana needed:

Steps

1. Activate Ashnod's Altar by sacrificing Brazen Freebooter, adding .
2. Brazen Freebooter dies, triggering Nim Deathmantle, causing you to pay to return Brazen Freebooter from your graveyard to the battlefield, and attach Nim Deathmantle to it.
3. Brazen Freebooter enters the battlefield, creating two Treasure tokens.
4. Activate two Treasure tokens by tapping and sacrificing those, adding two mana of any color.
5. Repeat.

Results