仙人になろうと修行を続ける蛇YOKAI姉妹の妹、青蛇(セイジャ)さん。
姉の白蛇が妹のような見た目と振る舞いをするため、周りから姉だと勘違いされる。
あざとかわいい姉とは真逆で、ガサツで男っぽく、無口ですぐに(拳で)行動してしまう。
実は美人だが、そのことを言われるのが嫌で、常にマスクをしている。
Seija-san, the younger of the Snake YOKAI sisters, who continue their training to become hermits.
Because the older sister, Hakuja, looks and acts like her sister, she is mistaken for the older sister by those around her.
She is the complete opposite of her mockingly cute older sister; she is crass, masculine, uncommunicative, and quick to act (with her fists).
She is actually beautiful, but she hates it when people talk about it, so she always wears a mask.