Morduval

Morduval was a servant of the Vampire King Swayne. He had the power to transform into a monstrous tentacle ... thing, but only for short periods of time. However, the transformation was so fast that from a combat perspective, he could be considered always to be in this form.
He also had a really nice suit, not that he kept it on most of the time, what with the bursting out of his clothes every time he transformed and all.
He was sent by Swayne to retrieve the Colana Dialiah from the Feywild (it is unclear as to whether or not he placed it there in the first place). Despite defeating Black, Draven, Mahar and Little One, he was killed by Angel.
He also had some mysterious glowing runes given to him by the Mindhunters that boosted his armour class. From his dialogue with Lady Hazamura it can be inferred that Morduval served the Mindhunters in some capacity, although it is unclear as to whether this was in place of or in addition to his loyalty to Swayne.