http://fireemblem.wikia.com/wiki/Kellam

Kellam's supports reveal that he grew up with five brothers, but his family was very poor, and he never had many commodities that other children had growing up. In a support with Nowi, he mentions that his lack of presence first began when he was younger and still living with his family; since they were poor, they had to share a lot, but he was mean and did not like sharing. Eventually his family got tired of him being so selfish and began ignoring him. This would later have a profound impact in his future, as most of the people he talks to are usually shocked (excluding a few, such as Cherche).