ShadowSeraphimon is a villain in Digimon Frontier, and one of the alternate form of Mercurymon. He's also known as BlackSeraphimon.
ShadowSeraphimon is a Mega Level Digimon that resembles an evil version of Seraphimon with ten purple demonic wings instead of the ten golden wings and a face shaped like an X.
Digimon Frontier
Mercurymon used Seraphimon's data to become ShadowSeraphimon. He easily fought Agunimon, then BurningGreymon, reverting him back to Takuya. Takuya gained a new power from Bokomon's egg and became Aldamon. ShadowSeraphimon was then defeated by Aldamon, reverting him back to Mercurymon, thus Seraphimon's data returned to Bokomon's egg.
Attacks ◾Strike of the Seven Dark Stars ◾Shadow Shockwave