Keeper of Ancestors

When Keeper of Ancestors enters the battlefield, create a Memento artifact token with "When this artifact enters the battlefield, exile target Spirit or legendary permanent for as long as you control this permanent" and "{t}: Add one mana of any of the exiled card's colors."
Whenever you tap a Memento for mana, if Keeper of Ancestors is in your graveyard, you may pay 3 life. If you do, return it from your graveya