Demon Lord 2099, Vol. 5 (light novel)

Demons and humans normally don’t mix, but in Shibuya, a massive geofront city, demonkind runs rampant and unchecked among humanity. This dark metropolis is where the Demon Lord Veltol finally reunites with his old vassal, May, who has lost most of her memories—but there is also a second May, a conniving Demon Lord who seeks to rule the world and overrun it with demons. Thus begins the fight to determine which Demon Lord will triumph, and only one can come out on top!