Kunoros, Hound of Athreos

Vigilance, menace, lifelink
Creature cards in graveyards can't enter the battlefield.
Players can't cast spells from graveyards.

Magic Online Promos

Three sharp barks announce an attempt to escape the Underworld. Three sharp bites end it.

Theros Beyond Death Promos

Theros Beyond Death

If an effect exiles a card from a graveyard and allows a player to cast it, that player may do so. The spell is cast from exile, not a graveyard.

Look at the card as it exists in your graveyard to determine whether it can enter the battlefield. For example, Sculpting Steel (a noncreature card in the graveyard) can be put onto the battlefield as a copy of a creature, but Phyrexian Metamorph (a creature card in the graveyard) can’t be put onto the battlefield, even if it would copy a noncreature artifact. A Theros Beyond Death God creature card can’t be put onto the battlefield regardless of your devotion to its colors.

Players can still play lands from graveyards if an effect allows them to do so.