Diamant

Diamant: The shining star of the child idol duo her and her brother Merak's parents thrust them into.  Though she tried to protect and guide her brother where she could, she and him were both exposed to a lot far younger than they should've been.  Though she rather enjoyed the lavish parties and intoxicants, she could tell it bothered her brother greatly.  She knows, deep down, he wants to leave idoldom behind, and as hard as she tries to accept it, it's terrifying to her.  

Diamant doesn't really know who she is outside of this duo, who is she without her brother to balance her out, just a spoiled floozy?