Nitroplus, sometimes written as Nitro+, is a Japanese visual novel developer who has developed a number of visualnovels, including eroge. They have also have been collaborating with TYPE-MOON (another developer) to create the light novel series, Fate/zero. Their works usually have dark themes such as reanimation of the dead and murder. They also have a branch of the company called Nitro+Chiral of which focuses on BL visual novels
They also released a fighting game Nitro+ Royale -Heroines Duel- (ニトロ+ロワイヤル -ヒロインズデュエル-) at the 2007 Comiket.
They also on January 25,2008,released minigame disk "CHiRALmori" under this branch of which uses chibi versions of the characters from Togainu no Chi and Lamento