Ninivit spent a lot of his childhood pretty peacefully, and with a looming sense of being talentless and overlooked that he never quite shook, on top of the general discomfort in his niche middle-kid role. Within a large and successful family, the kind and gentle ysoki was most notable for a decent (but not life-saving) rapport with animals, especially rats, and he took care of quite a few as pets over the years. Though he decided to make something of himself by helping with hunts and combat-heavy jobs, he really didn't enjoy tracking or hurting wildlife, and didn't want to commit to magic because of the aesthetic perception involved, something he would eventually come to regret sometimes.
Eventually the uncomfortable, unhappy child focused on the one "practical" thing he felt he could do really well, and he was in fact very good at martial combat with enough training and grit and desperation...but he still wasn't entirely happy with himself or his life, especially when brought along as the muscle to jobs he didn't like the goals of. (Especially the ones for Goka.)
He was just starting to figure some things out and look for alternatives when someone left for the New World. His life and work stabilized for the better once he finalized his decision and brought disparate, misunderstood parts of himself into a semblance of harmony, but again he came to feel something was missing. Curious about the land beyond the portal, he eventually left all of his earnings with his family, save the bare minimum needed to follow her halfway across the world and into another.