The enemies within the cave should not be difficult to defeat unless the Hero is either low leveled or fighting multiple enemies at once. One can also be infected with Porphyric Hemophilia while fighting the vampires.
They are generally a mix of vampire crusaders, warriors, mages, and agents. The mages tend to summon headless zombies and shoot destruction spells from a distance, fleeing deeper within the cave if approached. The warriors will simply cast a few defensive spells and charge into combat. The Agents shoot with bows and will switch to melee weapons once approached. The vampires carry leveled weapons and armor with them as well.
One of the vampires, a Redguard swordswoman, is more sociable than the rest, and will talk to the Hero. However, her dialogue options are very limited.