User:The Peterphile/Sadatsuna Ashiya

Sadatsuna Ashiya is a character mentioned in the Jujutsu Kaisen series. He is a sorcerer from the Heian Era, the founder of the New Shadow Style "school of thought" and the creator of Simple Domain.

Shibuya Incident Arc
After striking Mahito with Technique Charge: Simple Domain, Kokichi Muta exposits the origins of Simple Domain. Sadatsuna Ashiya, the founder of the New Shadow Style during the Heian period, devised a "domain for the weak", to protect his students from vicious curse users and cursed spirits. This technique became known as Simple Domain, and a binding vow forbid the technique from being deliberately taught to people outside of the school of thought. However, sorcerers who saw it in action were able to learn the technique by copying it, which is not accounted for by the binding vow.