There were five children in the Stark household and one half-brother, Lazarus, he was one of the eldest and was born from your father's first love.

Walking through the winter forest, you, Dan and Lazarus came across the corpse of a she-wolf, and under it there were five direwolf dark cabs

Lazarus: There's a wolf cub for everyone here.

Dan raised four wolf cubs and you one, and then Lazarus noticed a white wolf cub with red eyes, to which Dan snorted.

Dan: This is yours, Lazarus. Bastard.