The duel on skull mountain was a confrontation that occurred between Darkwolf and Nekron on top of the skull tower. It happened during the Battle of Icepeak, and ultimatley lead to the death of Nekron, and indirectly, the destruction of Icepeak.
Larn and Darkwolf were the only ones to get into Icepeak alive. Nekron, having already caused a cave-in when he sensed the battle nearing his throne room, climbed the skull tower and began to drive his glaciers further towards Firekeep. Darkwolf then climbed the tower behind him and called him out with a single cry of:
Nekron then drew his sword and ran towards his enemy, but when Darkwolf swung his axe, Nekron deflected the blow with a spell. Darkwolf tried multiple times to try and strike Nekron, but every time, Nekron held off the attack each time, with a cry of "Die-why don't you DIE!?!" However, Darkwolf's righteous anger was able to override Nekron's sorcery and he struck the Ice Lord a deadly blow. Nekron fell to the ground and writhed in fear as he realised that he had been defeated. Although he begged for mercy, Nekron died as Darkwolf struck him a second time. Nekron's violent death throes then caused his glaciers to push across the nearby river and King Jarrol was forced to release a lava flow which destroyed Icepeak for good.