The only known survivor of the failed Resistance attack on Adam Arclight. He appears to have a sister complex and is treated like a slave by Eve and Adam Blade.
A young boy who grew up in Black Spot, he often relied on his sister Aruka for protection, and as a result ended up sort of becoming infatuated with her. The two of them ended up joining the Resistance forces against Simeon.
One day, the commander of the resistance gave Cruz a special locket with a picture of his sister inside, and Cruz kept the memento close to himself after the resistance was massacred and Aruka sacrificed herself to blow up a Testament robot. After that event, he was nearly killed by another Testament as he escaped, but was saved with the timely intervention of the odd man in the priest's uniform, Adam Blade. With the help of people like Adam Blade, Eve Neuschwanstein and Gido, Cruz decided to find a way to fight back against Simeon as the last surviving member of the resistance.
Once he infiltrated Simeon's HQ with the help of Disk and co., Cruz discovered that his sister was actually one of Simeon's Elite Four, who had merely faked her own death and fed the resistance a fake attack plan so that they would be ambushed. Once they were all dead, Aruka could recover a microchip that the resistance carried that supposedly held info on the Second Jesus. However, both Cruz and Aruka discovered that the data was apparently hidden within the locket that Cruz carried.
Cruz was later able to escape Simeon's HQ after Adam Blade and Adam Arclight fought each other, and with the help of a lost Mio and Disk (or rather, Disk's head), Cruz tried to find his friends again. However, an accident ended up landing him in the St. Rose Academy where the Simeon Pretty Girl Squad held their studies. Thus, Kuchinashi and Setsuna were forced to quickly dress him up as a girl before anyone discovered his true identity. After a few hijinks at the Academy, Cruz ended up solving the mystery of the Needless student who planted bombs in the dorm rooms of high-performing students.
While he holds out confidence in his sisters abilities and motives, nearly to the end and only when shown undeniable proof that she wasn't what he thought did he face the truth. he has no confidence in himself and his abilities as an active and important part of the team. He makes up for the lack of confidence in himself by being a gopher for mostly Blade and Eve and doing so with little or no argument.
He is intelligent and has an ability to understand puzzles and combat often helping the team.
Though Cruz himself does not have any Needless fragments, he has proven valuable in his own right by using his brain to look for clues in solving puzzles and finding the weak points of enemies when other protagonists have trouble beating them.