Irys, Hope Personified

Irys, Hope Personified has indestructible as long as there are four or more historic cards in your graveyard. (Artifacts, legendaries, and Sagas are historic.)
Sage Project — Whenever Irys or another legendary creature you control dies, return target legendary creature card with lesser mana value from your graveyard to the battlefield tapped.

(Havi, the All-Father)