Apocalymon

Apocalymon is arguably one of the strogest Digimon in the television series "digimon". Apocalymon was born from the assimulated data of every Digimon that was "destroyed" by the Digital World's evolution. A sadistic & tormented soul, Apocalymon wanted to make the Digital World a living hell to justify those who compose him. It took a combined force of Wargreymon, MetalGarurumon, Garudamon, Mega Kabuterimon, Lillymon, Zudomon, Magna Angemon, and Angewomon to defeat him. But when he tried to commit sucide/genocide with his self-destruct Total Annilation, the DigiDestined sealed him with their Digivices so he would only kill himself.

Apocalymon would later appeared Fifth Digimon Movie (Not released in America), though it is a different Apocalymon, he was very much like last one. But when he was seemingly killed by Omnimon, Apocalymon's data reformed into a new evil to carry out his justice, Mephistomon.