This is a possibility if they put a curse at them or by a villain control them turn themselves against each other into evil forms until they come back to their normal selves again I hope you enjoying this

Lady of Darkness evil form:black hair and red pale eyes black lace long dress and long boots

Silent note evil form; dark purple hair with black streaks dark purple eyes tattoos on his arms and stomach

Hell petals evil form:white hair and blood red eyes dark red lipstick

Dark flower evil form:light pink vines like hair to attack green on right eye and dark brown on left eye

Negative electric evil form:black hair with yellow lighting strike black jacket with lighting strikes black pants yellow and black lighting shoes

Dark rain evil form:dark blue hair and black and blue eyes long sleeve dark blue dress and long boots tattoo tears on both cheeks

Dark tornado evil form;black eyes and white hair

Black sun evil form:left side dark orange hair and dark midnight blue hair on right side dark orange on left eye and dark blue on right eye the outfit is split on each side dark orange on left and dark blue on right side

Heart break evil form: pale pink hair and black eyes with empty broken heart on both cheeks

Glitch evil form: purple and green veil with flowers and black long sleeve jade dress black lip pale eyes

Dark star evil form:monk hair white tank top black short and black boots damage light strike on the arms and legs

(I hope you enjoy)