I couldn't finish 'em. Looks like this's gonna get complicated.
The Revenant is an enemy in Final Fantasy Dimensions. It is encountered in the Challenge Dungeon of the The Memorist part. Since the Challenge Dungeons do not appear outside the original phone release, it is only dummied in the other mobile versions and therefore not available in any English version of the game.
Revenants are animated corpses or ghosts in Western folklore that are said to return from the dead to terrorize the living. The word "revenant" is French (Fr. revenir, "to return") and means "one who returns".