Baron Nero is one of leading members of the Evil Army Shadow Line. He is the acting leader of the Shadow Line before Emperor Z's arrival.
As acting leader of the Shadow line, Baron Nero believes that amassing darkness is vast amounts is essential to bring Emperor Z into the human world. This leads to him clashing with Madame Noir over her prepping Miss Glitta and using her Shadow Creep followers to gather darkness by quality. When Emperor Z arrival is ready, Nero sent General Schwarz to retrieve their leader before learning Z left the Kurainer in prematurely to enjoy the sights in the human world.
Upon finding Emperor Z, Nero is shocked by his leader's obsession with light and initially dismissed it as a phase before becoming overly concerned when he learns Noir is using the wedding of her daughter to the emperor for her own ambitions. But after Z consumes Glitta, Nero accepts his leader's ideals that the Shadow Line must consume light to take over the world as he begins taking an more active role.
His voice actor also voiced Lelouch Lamperouge.