Megidramon is a draconic Dark Spawn lord that joined Malefor's ranks not long after his ressurection at the hands of Hexxus. He is one of the "Four Great Dragons" and his name comes from the word "Megiddo", the place where Christians believe the final battle between good and evil will take place. His body is wrapped in armor made of Chrome Digizoid. He is a rare (in fact, unique in every game) species whose reason for existing is unknown, but is said to be one of the very incarnations of the Digital Hazard, a power of malice that is sealed away by an unknown "force". However, when that power is awakened, he creates a system meltdown which could destroy the Digital World.
Megidramon is Guilmon's second Mega form when the full destructive power of the Digital Hazard is released Lionheart Give a Little Bit, and as a result his existence endangered the very fabric of the digital world. Megidramon posses acidic saliva, with The Hazard shown as the Digital Hazard symbol on its chest flashing red. The central triangle was permanently red, but the three triangles around flashed red. Once this started Henry realized that the symbol was a hazard and the ground under the groups feet started to crack and massive fissures were formed. Terriermon fell into one of these fissures while fighting Beelzemon. It was then saved by Renamon. Guilmon turned into Megidramon once when he Digivolved using Takato's anger. The death of Leomon at the hands of Beelzemon caused Takato to fill with blood lust. Jeri finally snapped him back to his senses and he became horrified by Guilmon's transformation (which also destroyed his D-Arc/D-Power in the English Dub).
At first, Megidramon seemed to have the upper hand against Beelzemon and attempted to devour him. However, Beelzemon eventually won the battle by absorbing Makuramon's data, beating Megidramon unconscious. Takato cried, knelt down by the unconscious Megidramon and wished that he and Guilmon could start over. But as soon as Takato realized that he couldn't give up the old Guilmon, Megidramon quickly changed back into Guilmon. Takato then wished that he and Guilmon could fight Beelzemon together as it should be. This resulted in him Biomerging with Guilmon to become Gallantmon. After the battle, Takato then received a new D-Arc, an Ultimate (Golden) D-Arc. Takato was the only one in the season to get a Golden D-Arc.
- Megiddo Flame: Megidramon exhales a vicious maelstrom of purgatorial flames.
- Hell Howling: Megidramon howls while facing the enemy; the shock of the sound itself is critical to most weaker Digimon.