At the beginning of your upkeep,
destroyThe only ways a permanent can be destroyed are as a result of an effect that uses the word “destroy” or as a result of the state-based actions that check for lethal damage (see rule 704.5g) or damage from a source with deathtouch (see rule 704.5h). If a permanent is put into its owner’s graveyard for any other reason, it hasn’t been “destroyed.”
A regeneration effect replaces a destruction event. See rule 701.19, “Regenerate.” (CR 701.8) the creature with the least power. It can't be regenerated. If two or more creatures are tied for least power, you choose one of them.
When there are no creatures on the battlefield,
sacrificeTo sacrifice a permanent, its controller moves it from the battlefield directly to its owner’s graveyard. A player can’t sacrifice something that isn’t a permanent, or something that’s a permanent they don’t control. Sacrificing a permanent doesn’t destroy it, so regeneration or other effects that replace destruction can’t affect this action. (CR 701.21) this enchantment.