Lost Mine of Phandelver
Red Wizard necromancer.
Kost is a stout, red-robed figure with sallow skin, a shaved scalp, and a black tattoo on his forehead.
The adventurers encountered Hamun when he was searching a ruin for Netherese artifacts.
The adventurers stood against Hamun and his zombie minions at Old Owl Well. They destroyed the necromancer and his undead servants and eliminated the the threat to the miners from Phandalin.