Boltmon is a Mega-level Cyborg Digimon, who joined the battle against D-Reaper.
As the D-Reaper prepared for the attack, Azulongmon asked Calumon to use the evolving light to make the Digimons stronger and join the fight against the D-Reaper. And Boltmon joined the battle as it evolved to the Mega level from its previous form.