Runty is the offspring of . As his name implies, he is the runt of the litter of four pups. He can be found in his own little area behind and to the right of Beauty, frolicking near the lava pools within Beauty's Lair[66.6, 84.6] of Blackrock Caverns.
Further evidence of his runt status lies in his buff:
Players wishing to kill his mother should avoid killing him prior to engaging her, as she goes berserk and is able to quickly wipe groups.