Ulyaoth has two circles of planet-like orbs surrounding him, with the smaller circle (both in diameter and orb size) floating above the larger one. These constantly circle Ulyaoth and may be a nod to how movement generates/restores magick for player characters. They also could be seen as crowns of sorts.
Ulyaoth readily admits that his knowledge is inferior to Mantorok. However, casting a Mantorok [Recover] spell regenerates only sanity and health, not magick that Ulyaoth has dominion over. While this can be considered a game balancing issue, it could also hint that Ulyaoth has at least a modicum of resistance against Mantorok, unlike his peers. Parts of Ulyaoth's Black Guardian also turn purple, the color of Mantorok, when it is recovering power in its fight against Peter Jacob, and enchanting Michael Edwards' flashlight with Ulyaoth's alignment creates a somewhat purple light as well. This might suggest that, among the three Forbidden City Ancients, Ulyaoth may be the closest to Mantorok's level.
Ulyaoth is depicted as a sorcerer in Michael's chapter in the room with bas-reliefs of human representations of the Ancients.
Ulyaoth Enemies drain your magic during battle AND take away your health, however health damage taken is the same as Xel'lotath Enemies.