Played a bunch 13th Age, let’s try my hand at this!
Adventurer Tier: When the escalation die is an even number, gain a +1 bonus to all saves. For the purposes of this feat, 0 is not an even number.
Champion Tier: When the escalation die is 1 or greater, gain a +1 bonus to all saves.
Epic Tier: The bonus to saves from the champion tier feat is now +2.