So I have mentioned a few times, mister Bernard here was used for experiments as the lich that raised him as a death knight searched for ways to enhance his creations and make them even more powerful. It didn’t go the way he planned it, and Roteye ended up as a failed experiment – but a damn vicious and strong death knight nonetheless. But that’s where his odd looks come from – the mutation wasn’t complete, but the claws, fangs, pointy ears and odd hue of his skin, as well as his above-average height stayed.
And if the lich would have been successful, then he’d look like the first picture, welp.