About

Masamune was born a long time ago, in fact, he doesn't remember the year he was born as it's been a long time since that happened. He is a demon, that controles plants and more largely nature in general. He is detached from reality, in his bubble most of the time. He is really fast and agile, and smart. He isn't under Muzan's controle and thus doesn't kill humans. He lives in an abandonned house in a random place, isolating himself from the world.

His familly never accepted him, he wasn't desired at birth and was a mistake to the family. He was often beaten by his mother and father, and On top of that he is really tall, really really tall, and his delicate nature made him look like an anomaly. This was the reason why most of the village he was living him were avoiding him. His family used him to work for the family business, which was gardening and cultivating vegetables and fruits. He grew to like nature as he spent most time of his life around it. His mother tried to marry him to someone for money, but the girl refused the marriage, as he was too tall and too weird. 

He never really experienced love, and thus he distanced himself from the world, trying to protect himself from the pain and judgement of the other. One day, as he was working hard, he came back home late and discovered his familly slaughered by a demon, only his mother was still alive, the demon still there, he did everything he had in his power to save her, but he was too weak against him, Muzan. After a short fight, Muzan gave him his blood, a lot of it, trying to kill or to see if he will survive, and he did, miraculously. He transformed into a demon, but in this fated night, the hatred he felt for the high ranked demon was so strong that his will to revenge made him kept his humanity. He was strong, but he promised to never use his powers to hurt anyone.
He then isolated himself in an abandonned house he found, contemplating the idea to let himself be killed by a demon slayer, or to just have himself in front of the sun, but never had the courage to. 

Maybe someday he will find happiness in his miserable life.