Nero L

Nero L (ネロ・L) is a boss from Rockman Xover that appears in World 12 and the Battle Tower. He is the leader of Blu D, Rosso M, Oro S, and Verde R. He has two attacks, one where he jumps in the player's direction and quickly falls with his sword for a strong impact slash, and other starting with him dashing to stab the opponent and following with a rising slash.

His story is completely unknown.

When all main worlds are complete and all their bosses reach level 8, Nero L appears and decides to help OVER-1 by giving him a Portal Charger (ポータルチャージャー) so he can rescue the missing Mega Man heroes.

Archie Comics
While he did not appear in the series proper, Nero L is one of the many characters featured in the Short Circuits for Mega Man Issue 55, the concluding issue of the series prior to going on hiatus. He appears with OVER-1, the pair being jointly described as "The Mobile Phone Mega Men" while X and Mega Man look on in chagrin.

Etymology
Nero means black in Italian.