i'm not sure maO ba to cause. i'm guessing 'cause like undercover_lover said, that's when the mask made its first appearance. and diba hollows aren't born, they're made? so maybe it's not something he inherited? i could be wrong. this is all just pure speculation.
OT: kabantay mo Spanish ang terms sa Hollows? hueco mundo, espada, menos grande, adjuchas, vasto lorde...hehehe. wala lang.