Gulfmon is the main antagonist in the movie Digimon Tamers: Battle of Adventures, and he is Mephistomon's true form and alter-ego.
Gulfmon is a Mega Level Digimon. He is Mephistomon's much larger and more powerful but less intelligent form. Gulfmon is built like a giant beastial winged centaur. He has a second hidden mouth on his lower torso. He is as huge as a mountain. It's said to be connected with an abyss in the Dark Area, and if inhaled, an opponent's DigiCore is smashed to pieces.
He lurks within the deepest parts of the Dark Area but appears on the surface in order to destroy it.
The Tamers' Champion Digimon are unable to scratch him, but Calumon's powers activate, digivolving them to Ultimate. As Gulfmon charges at them, they combine their powers into their "Trinity Burst" attack, impaling and destroying Gulfmon.
Digimon Xros Wars (Manga)
Though Gulfmon didn't make an appearance, DarkKnightmon Darkness Mode (Duskmon) apparently absorbed a Gulfmon and became DarkKnightmon Darkness Mode (Gulfmon).
- Dead Scream: Unleashes a deafening shriek killing anyone who listens to it.
- Black Requiem: Using his second mouth he releases dark energy from the Dark Area.
- Gulfmon is the voiced by Richard Epcar, the very same voice actor who voiced both Myotismon, and the less threatening antagonist; Etemon, as well as thier alternate forms. He has also the voice of the first antagonist in Digimon Data Squad; Merukimon.