Regro found Mash abandoned as a baby on a bridge and decided to raise him alone in a secluded house deep in the woods. He kept Mash isolated from the outside world, warning him never to go near the city—the reason being that Mash had no mark, and authorities would take him away if discovered. To prepare Mash for the dangers he might face, Regro focused on building him up physically, training him to be strong enough to defend himself.
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