Sulla may have been part of the Imperial Legion, but possibly deserted to explore Alftand. Before going to the ruins, he gathered a crew composed of Umana, J'darr, J'zhar, Endrast, Yag gra-Gortwog and Valie. He left the Expedition Manifest at the entrance of the ruins describing the members of the crew and the roles each one fulfilled for the expedition. He wrote Sulla's Journal, which describes his ill-fated attempt at excavating the ruins. Inside, they found some Dwarven spiders that were disposed of easily. Afterwards, he began researching them and wrote the Research Notes.
His knapsack is in the torture room where Valie is found. Among its contents is an Imperial officer's helmet along with some common items.
His fighting tactics are simple. He uses Fireball as his primary attack. When he runs out of magicka, he engages in melee combat. If his health goes very low, he flees from combat and uses Fast Healing. When his health has recovered enough, he continues to fight.
- After Sulla Trebatius is defeated, his body can be searched for a rare enchanted Imperial sword. Its enchantment type is entirely random, but the strength of the enchantment is always the same (equivalent to 10 points of damage).
- It is possible that he may be a descendant of Vandorallen Trebatius from Oblivion.
- He makes a good dead thrall because his body is permanent, meaning he can be used multiple times if his location is known. His armor can be enchanted to make him stronger and he still heals himself during combat.
- Given that his pack contains an Imperial Officer's Helmet and that he is clad in Imperial Armor when encountered in Alftand, he was likely an officer in the Imperial Legion, though he presumably deserted.
- As mentioned in his journal, he harbors a strong dislike of the College of Winterhold.
- He does not seem to be concerned that his foolish and ultimately failed expedition resulted in the deaths of his entire team save himself and Umana.