Skull of the Holy Revenant: While equipped, you will respawn 75.0% faster.
Valiant Emblem of the Phoenix: While equipped, you will respawn 50.0% faster.
Emblem of the Phoenix: While equipped, you will respawn 25.0% faster.
As of 1.9.10, the Skull of the Holy Revenant variant can cause you to not respawn at all if you die atop a packmaster hook. This is caused by your dead corpse not being removed yet by the time by which you should respawn, which confuses the game and breaks the respawn process. A player being stuck in this permadeath state will also potentially stop the game from ending even if all players are defeated. It is possible to fix this and force a respawn by rejoining the game, as long as the victim is not also the host of the game.