in the manga collie's power kind of looked like a snakes, kuki or whatever her name is also seems to be based on snakes

also in the end of the manga collie went back to sumeru to study, kuki graduated(?) from sumeru

collie was for most of the comic a criminal, it would make sense for her to change her name and start wearing a mask around

also kuki's outfit seems to have some inspirations from amber, collie's first and only friend

there u have it folks, collie went to sumeru and changed her name due to everyone basically kicking her out before, she got an electro vision and left to inazuma, before she met with itto, a friendly yet dumb oni with high hopes (reminds her of amber) and collie officially joined his gang and started going by the name "kuki"