OP of the new BL game, Kimi no Naka no Palldium (君の中のパラディアーム)

Official site: http://chaterrant.jp/

Song: Rakuen no Kagi (楽園の鍵)

Artist: Shimotsuki Haruka (霜月 はるか)

Plot: There used to be a world called palladium ruled by the god of white wings and the god of black wings. They had a fight and palladium was separated into Fontene (humans with white wings) and liberte (humans with black wings). One day, an unconscious human was found by the roadside of liberte. His name is Aile and he ran away from his cruel orphanage. He is the first wingless person ever found and suffered terribly for it. The one who found him is a black winged human named Vanvert, who says they are brothers. They must go on a journey to find their two missing brothers. What caused the four brothers to separate and why doesn't Aile have wings? More importantly, what was the cause of the fight that split up paladium? (less info)