Activate Relic of Legends' second ability twice by tapping Lurrus and Saffi, adding .
Activate Saffi by sacrificing it, targeting Lurrus.
Activate Ashnod's Altar by sacrificing Lurrus, adding CC.
When Lurrus dies, Saffi triggers, returning Lurrus from your graveyard to the battlefield.
Cast Saffi from your graveyard by paying .
Repeat.
This brilliant loop leverages Saffi Eriksdotter's self-sacrificing rescue trigger to continuously save Lurrus of the Dream-Den from the brink of destruction. Every time Lurrus hits the graveyard, Saffi's delayed trigger immediately returns the cat nightmare to the battlefield, while Ashnod's Altar converts Lurrus into a pair of colorless mana to help fund the operation. Meanwhile, Relic of Legends taps both legends to generate the exact colored mana needed, and Lurrus of the Dream-Den's own static ability allows Saffi to be repeatedly recast straight out of your graveyard for a seamless, self-sustaining engine.