A small side quest in Hallowfall involving earning the trust of a wary Arathi soldier has a unique variant for player characters such as void elves, undead, demon hunters and warlocks, in which he not only comments on your dark nature, but offers an additional quest to prove your worth.
The inhabitants of Hallowfall have a deep-seated distaste for the powers of the void. They not only hail from a distant Empire ruled by a prophetic holy Emperor, but their mission at his command involves seeking power to fight in what they call 'Renilash', the coming clash between the forces of Light and Darkness. In their quest for this power, they were caught in a massive storm, and teleported below ground in a flash of Light, finding themselves in a massive cavern that they were now stranded inside. There, they not only fend off dark forces such as the Nerubians and Kobyss, but weather against the onslaught of dark magic that results from their guiding star, the massive holy crystal of Beledar, turning dark on an unpredictable schedule.
Beledar, cast in both light and darkness.
In the Arathi outpost of Dunelle's Kindness, you can find a couple named Lerrenai and Derill Fayn. While Lerrenai seems rather tolerant towards the player, Derill acts rather distinctly distrustful, demanding that you prove your worth and complete a simple task of pest control for him. For most players, this will simply be shown as a matter of suspicion amidst their stressful circumstances, but for players of a race or class that wields dark magic, he has an extra word of distrust for your shadowy nature.
Derill's suspicion towards regular players.
Derill's adverse reaction towards players such as void elves.
For other players, the questline ends after this simple task, but for those he distrusts for their magic, Derill's ill gaze towards you has not quite dissipated, and he demands another task to prove your worth.
In