Grimoire of the Dead [Commander 2019] Elemental Knight Counters aren't removed from your

Counters aren't removed from your permanents due to game rules

then each opponent loses life equal to the sacrificed creature's power

and has "At the beginning of your upkeep

Flashback {4}{G}{G}{G} (You may cast this card from your graveyard for its flashback cost

Set: Collectors’ Edition Type: Artifact Rare Cost: {4} All Swamps are 1/1 black creatures that are still lands

Grimoire of the Dead [Commander 2019] Elemental Knight Counters aren't removed from yourSet: Commander 2019 Type: Legendary Artifact Mythic Cost: {4} {1}, {T}, Discard a card: Put a study counter on Grimoire of the Dead. {T}, Remove three study counters from Grimoire of the Dead and sacrifice it: Put all creature cards from all graveyards onto the battlefield under your control. They're black Zombies in addition to their other colors and types.