emiya hails from a small familial pack comprised of her parents and grandparents, her older brothers, and litter-sister. the group is very careful about keeping to themselves; they do not dissuade their children from adventuring in to the wilderness (and in fact the family have a strong tie to the balance of nature), but the children were raised apart from larger societies and the ways of outsiders.

it was nagisa, one of her brothers, who wished to disperse first. tetsuzan tried to reason with him, and the two came to blows as their rivalry often spun-out to the kind of sibling violence that was there one moment, gone the next; however, this time it went too far, and nagisa vowed to never return. this broke emiya's heart. she wanted the family united and together, and could not fathom why anyone would want to leave.

after some encouragement from her grandmother lutra, emiya realized she wasn't heartbroken for the loss of her brother (for he wasn't truly lost, only angry, and that would pass) but jealous that he was going on an adventure, and leaving her behind. she sought out her parents to ask permission to go, and was surprised by their encouragement. she then went to her sister tooka, who went everywhere with her always, and tried to convince her to travel with her. that failed, and caused a rift between them that had never been there before.

regardless, emiya saw the chance for adventure and independence. it was frightening to leave home (especially without her sister, the shadow), but she trusted in the world around her (perhaps too naive about it) and after her farewells, dispersed, to hunt for adventure in the wide world.