Seeing this thread ressurected actually reminds me of this OC I made several years back.
Fukui Hibiki was a freelance mage with a biting demeanor, relying primarily on runes and other written magic. Ordinarily he worked together with his teacher, an eastern combat mage who also resorted to demonic magic. Son of a japanese onmyoji working as a freelance exorcist and an orthodox western mage from England; when he was some 7 years old his father failed to return from an investigation mission for his employers, and his mother died not long after from the backlash of a curse she removed in her line of work. His mother's cousin, Sakurama Kazuya, was the one who raised him from that point onwards and started to train him, which led to Hibiki eventually joining the same jobs as a mercenary.
Most of his magic didn't use incantions. Instead he used a Light Scribing spell to project written magic formulas on the air and enact complex spellcraft through them. Since he had unusually efficient eidetic memory, instead of dedicating it to remembering lines and lines of text from spell books, he used it to memorize rune sequences, magic circles and geometrical magical equations with perfect precision.
Essentially, instead of casting magic, he wrote out magic, with greater and faster results than regular spells once he dominated Light Scribing to the point he could instantly project meters and meters wide complex arrays. He still used essential magics without much difficulty, but they weren't the core of his abilities. He was trained in martial arts, but he didn't practice any one in particular and just mixed efficient moves in the most straightforward way in combat. His resilience and strength were greatly increased, even without any special focus, from the runes he had also engraved on himself.
All around, his skillset made him a formidable fighter at most ranges. His major weakness was that he wasn't fast when compared to other fighters in his weight class.
I originally came up with him for a Negima fanfiction where he'd get sent off to be Negi's assistant, and his teacher was an expy of Sakurazuka Seishirou that I had actually conceptualized earlier. His character arc, as I initially envisoned it, was going to revolve around him finding a life he wants to protect with the people he meets at Mahora Academy, and deciding to help some of them with their own objectives, instead of just keeping up with his work and satisfying himself with having the chance to help others every now and then.
