Her personal name Seija (正邪) can be loosely translate as "good and evil," or "right and wrong." , while her last name Kijin (鬼人) is spelled with characters meaning "oni" and "human"."邪" and "鬼" from her name are both characters that make up the name of her species, Amanojaku (天邪鬼). Although her personal name has the character for "oni" and her species is often depicted as such in Japanese folklore, amanojaku are not a type of oni.
If you listen hard enough, you can pick up bits of Toyosatomimi no Miko's theme in her theme.
Her theme sounds roughly the same backwards as it does forwards.
Seija is the sole Touhou character no Gensokyo resident has seemed to like in canon. Before this, Satori Komeiji was the closest.