Gornog, the Red Reaper

Gornog's third ability overwrites the target's existing creature types. Once the ability resolves, that creature will be a Coward and won't have its previous creature types. It retains any other types and supertypes it has as well as any subtypes that aren't creature types.

Gornog's third ability doesn't have a duration. It will remain in effect until the game ends, the target creature leaves the battlefield, or some subsequent effect changes the creature's characteristics, whichever comes first.

The bonus granted by Gornog's last ability changes as the number of Cowards your opponents control changes.