One

Nikko Murakami is a normal teenage boy with a normal life. He goes to university, lives with his mother and sister, and has two best friends Ume Toshima and Remi Otsuka. Nikko's life dramatically changes on his nineteenth birthday when a demonic entity begins disturbing his peace. Nikko soon learns the reason behind the entity is because his father, sky guardian - Ayumu Murakami gave his soul to a demon. On Nikko's 21st birthday the demon will have access to his soul. Follow Nikko on his journey to discover his own abilities and learn more about his father's past. This self-discovering journey includes friendship, battles, romance, trust and betrayal.