Zero was a former luchador, growing up in constant violence until he managed to join the UNSC as a means to escape the lawless lands. Soon he left to join Charon Industries, finding the UNSC too dull and hoping that Charon Industries would provide him with a true challenge.

He is often quiet and brooding, avoiding needs for conversation and more focusing on needs for violence. The only thing keeping him from turning into a viscous cold-blooded killer is his only family, which often reminds him of what he could eventually be. Zero often takes pride in his accomplishments, reminding his enemies of his many victories and at times using this to taunt the enemy further.