She is Black Star’s Dark Demon Blade partner. She can change into multiple ninja weapons (shuriken, smoke bomb, katana, chain scythe, etc). She is most of the time disheartened by Black Star’s loud self but she still puts up with it because that’s what she likes about him. She has a very forgiving personality and always tries to help everyone even when she has no idea how to help. Tsubaki soul is “very co-operative and has a lot of space to accept people” as said by Dr. Stein.