There are a few situations that should be addressed.
The first situation involves Rest in Peace. It basically says, “If a card would go to the graveyard, exile it instead.” This simple line prevents Athreos from triggering upon the destruction of a creature. Why, you may ask? The answer is rather simple. The word “dies” means a creature going from the battlefield to a graveyard. Rest in Peace prevents the creature from ever going to the graveyard, so, Athreos takes a rest, and doesn’t act, leaving your opponent to enjoy some peace.
The second situation involves a token. If a token is anywhere other than the battlefield, it ceases to exist when state-based actions are checked. This, however, does not stop Athreos from triggering. When a token dies, Athreos will present your opponent with the following choice: “Pay three life or nothing happens.” A token that has left the battlefield can never come back.
Today’s Rules Tip written by James Arriola