ChaosGallantmon

ChaosGallantmon (known as ChaosDukemon in Japan) is a fictional character from the Digimon media franchise, a Mega Level Evil Warrior Digimon, the evil form of Gallantmon. It is said that ChaosGallantmon can slide evolve into Megidramon.

Digivolution
ChaosGallantmon's Digivolution line in the D-Ark Version 1.0:
 * Rookie (Child) - Guilmon
 * Champion (Adult) - BlackGrowlmon
 * Ultimate (Perfect) - BlackWarGrowlmon
 * Mega (Ultimate) - ChaosGallantmon

ChaosGallantmon's Digivolution line in the Digimon Rumble Arena 2:
 * Rookie (Child) - BlackGuilmon
 * Champion (Adult) - BlackGrowlmon
 * Ultimate (Perfect) - N/A
 * Mega (Ultimate) - ChaosGallantmon

Attacks

 * Demon's Disaster: Fires lightning bolts from his shield.
 * Judecca Prison: Encases his opponent in a lightning "prison" created from his lance.

Digital Monsters: D-Project
ChaosGallantmon evolves from BlackWarGrowlmon.

Digimon Rumble Arena 2
ChaosGallantmon was in Digimon Rumble Arena 2; he only appears after unlocking BlackGuilmon, then Digivolving him twice.

Digimon World DS
You can obtain a Digiegg containing ChaosGallantmon if you Match BlackWarGreymon and BlackMegaGargomon. Afterwards, any Antylamon can evolve into ChaosGallantmon depending on its stats.

BlackWarGrowlmon, despite being ChaosGallantmon's true ultimate form, cannot Digivolve into ChaosGallantmon.