Allegro is a character that appears once in MegaMan NT Warrior Axess. It is a robot built by Bass.EXE. He captures NetNavis that win a game at an arcade and forces them to fight each other to the death for his amusement. Mayl and Roll.EXE win the game to lure him out and Roll is captured shortly after. They manage to track down Allegro and corner him. He then bursts out crying and Bass in Kid Grave's body comes and explains Allegro's origin. He was a robot created by Bass as a brother but stated that he was disgusted by Allegro and crushed his chip, killing him.

From MMKB, a Wikia wiki.