Atsumu was born in the wind dominant branch of the Yaseimei Clan, a clan that was a member of the Fang tribe. His nuclear family was a middle of the road family among the clan. They had no produced anyone exceptionally powerful in the past, though his father had made it to full hunter status prior to his birth. His mother was a trophy bride, taken from the ruins of a clan that had dared to raid the fang. As such he was of fairly good stock, and expected to be a solid, albeit uninspiring, member of the clan.