Seija Kijin is an Amanojaku who lives in the Shining Needle Castle. She appears as the Stage 5 Midboss and Boss and also Stage 6 miniboss of Double Dealing Character. Seija plots social upheaveal and uses Shinmyoumaru Sukuna and her Lucky mallet to achieve this.
She thinks that a good idea is a bad idea and a bad idea is a good idea. This makes the Lucky Mallet and its effects the more interesting to her.