“No matter who’s after my life, I have no reason to return this wonderful power!”
Seija Kijin is the contrarian mastermind behind the incident in Double Dealing Character and as of the newest game, Impossible Spell Card, a wanted criminal.
No one likes Seija. This isn’t an exaggeration. It’s completely intentional and Seija wouldn’t have it any other way. She is an Amanojaku, a particularly sinister type of youkai that drives people to commit wicked deeds by drawing out their darkest desires. Some Amanojaku, Seija included, revel in being hated and loving what others despise. Essentially, they’re supernatural hipsters.
While she has horns and is described as having a vaguely Oni-esque appearance, Seija is not an Oni and her deceitful nature would likely make the comparison quite insulting to Oni like Suika and Yuugi. Indeed, she made her entrance into Touhou by deceiving Shinmyoumaru into declaring war against the youkai of Gensokyo, simply to get her to use the Miracle Mallet to cause chaos.