Thomas was one of two demons who attempted to free Lucifer from captivity.
Background
When Crowley began acting strangely, Thomas and another demon suspected the King was hiding something, potentially the Archangel Lucifer himself. In order to find out for sure, the two demons freed Ramsey from her kennel, causing a distraction.
The two demons then approached Crowley with a list of crossroad deals that needed his attention. Crowley agreed to hear the list but he was not at all interested. When a call came in from Dean asking about the hellhound, Crowley was then distracted.
Using a key the other demon snatched from Crowley, Thomas and he were able to enter Lucifer's cell and meet him for the first time. Thomas immediately dropped to his knees, declaring that he was unworthy, while the other offered to help in exchange for power.
Lucifer pretended to agree so the pair would finally free him from his chains, though he was pleased with Thomas' request just to make Hell great. Once the task was done, Lucifer instantly obliterated the demanding demon. He then told Thomas that he could not leave any witnesses behind, though Thomas offered himself up gladly, saying his body was Lucifer's to devour, much to Lucifer's discomfort. Lucifer obliterated him too.
Ultimately, their plan failed as Lucifer's true prison was his own vessel and Ramsey was soon killed by Sam Winchester.
Powers and Abilities
Thomas possessed the basic abilities of all demons.
- Demonic Possession - He required a vessel to walk the earth, and did not require their consent.
- Immortality - As a demon, Thomas would not age or die unless killed.
- Invulnerability - He was immune to normal forms of harm.
Weaknesses
- Higher Demons - He was subservient to Crowley.
- Archangels - Lucifer was effortlessly able to kill him.