Shiro (Nude) (Patreon)

This is Shiro, looks like a little girl but it's actually a 18 year old male summoner living in modern Kyoto. With antics that make him contrast like black and white (and probably oil and water) with his twin brother Yuuki, such as cosplaying cute female characters and his heart and soul melting at the mere sight of something cute along with his extremely sadistic tendency towards his poor familiar, which he calls dog.

Shirousagi tells the story about the two kids who after years of training finally reached adulthood and became official summoners, finally getting to protect Kyoto from the demons that lurk in the night, while enjoying their lives as members of a rich family of magicians during the day.

The picture, with a little cropping  magic should fit as a wallpaper in case that you want to use it.