Cruz's sister and secret member of Simeon's Elite Four. Has a Fragment that lets her increase the speed of molecules in the air around her, generating large amounts of heat and can make things explode by touch.
Aruka was Cruz's big sister who apparently forgot to wear a shirt when the Resistance went all-out to assassinate a supposedly vulnerable Adam Arclight. When Simeon's Elite Four ambushed and wiped out the Resistance, she sppeared to give up her life to help her brother escape through the sewers. In reality, she faked her own death and thought that another Testament would finish off Cruz, but she didn't count on the introduction of Adam Blade.
Aruka was one of Simeon's Elite Four from the start who infiltrated the Resistance in order to locate a special data chip that Arclight wanted, and when she could not find it she fed the Resistance some false information that led them into a trap where they were massacred. Even then, Aruka couldn't find the data chip in their base or on their dead bodies. After deciding to fight the assembled good guys who made their way into Simeon's own Third Shelter, it turns out that the leader of the Resistance hid the data chip in a locket that Cruz carried, thinking that Cruz was the one person Aruka would never harm. Will she find the strength to kill her brother and take the locket? Signs currently point to yes.