He has served in many armies, usually as a scout and tracker. He is a swordsman on par with Conan, although he is more disciplined and less destructive. He is also a master of the bow, having served beside Hyrkanian archers. He is older than Conan, and when the two meet it is a source of rhetoric between the two. However, he is still very strong and tough, and his age is more a source of caution than weakness. Nestor is calm, disciplined, and careful, whether in thieving, warfare, or even conversation.
He has blonde hair and beard, and is very muscular. He usually wears simple, practical clothing.
Nestor is an honourable man, and during his relationship with Conan they earned one anothers' respect. Initially, Conan's braggadicio and ego offended the more restrained Gunderman, and they were rivals for a time. However, as they shared more experiences they came to be more friendly, even looting the Hall of the Dead together.