|This article is about the TV Series Prison inmate. You may be looking for his Comic Series counterpart.|
- "Ain’t gotta tell us how to take out a man."
- —Tomas to Rick Grimes after being told how to kill walkers[src]
Hardly anything is known about Tomas' life before the outbreak. He was a convicted criminal being held in the prison, but it is unknown what he was imprisoned for.
Although his personality is not well known, Tomas was shown to be an untrustworthy, sly, hostile and homicidal individual. He was shown to be a remorseless, cold-blooded murderer as shown when he murdered his ally Big Tiny after the latter was infected, and then tried to murder Rick Grimes twice, an act that eventually led to his own demise.
In the outbreak's onset, a big rebellion started at the West Georgia Correctional Facility, where Tomas had been imprisoned. Tomas, Oscar, Andrew, Big Tiny, and Axel were taken to the prison's cafeteria by a guard. Tomas reports that the guard gave him a gun, locked them in, and then left to call for backup, but the guard never returned and the five prisoners spent 10 months locked inside the cafeteria without fully knowing what was going on outside.
Confused about what had just happened, Tomas and the other prisoners ask who Rick and his group are, thinking that they are bandits that have raided the prison. Rick tells Tomas and the others about what has happened to the world, which the prisoners were totally unaware of. Realizing that this prison is the safest place to live, Tomas threatens Rick's group, claiming that the prison belongs to the prisoners, and Rick and his group must leave. After an intense discussion, Rick make an agreement to attain a share of the cafeteria's food in exchange for helping the prisoners clear out walkers from a cell block for the prisoners to live in. During the process of killing walkers, Tomas acts increasingly belligerent towards Rick and the others. Big Tiny gets deeply scratched by a walker and says he feels fine and nothing was going to happen. As the other prisoners ask Rick if there is any way of saving Big Tiny's life, Tomas kills Tiny with no hesitation by brutally smashing his head in. This raises concern for Rick and Daryl, who prepare to take him out if he makes any further hostile moves. Later, the group enters the laundry room with the entrance to the other cellblock, and Rick instructs Tomas to open a single door. After opening both and allowing in the full group of Walkers, Tomas justifies his actions by saying "Shit happens." While the group members are killing walkers in the laundry room, Tomas then intentionally swings his weapon too close to Rick whilst attacking a walker, and then pushes another walker onto him; Rick manages to survive after Daryl stabs this walker in the back of the head. The prisoners finish killing the remaining walkers. Tomas shrugs it off with a comment, to which Rick nods his head and agrees, saying "I get it. 'Shit happens'"; then after they stare each other down, Rick drives his machete into Tomas' skull, killing him.
After Tomas kills Big Tiny, and tries to kill Rick twice in a row, Rick approaches Tomas, and after an intense confrontation, he mercilessly drives his machete into Tomas' head, killing him instantly.
This list shows the victims Tomas has killed:
Andrew was apparently very close to Tomas as shown by his willingness to go along with Tomas' decisions; this is revealed through comments made by both Axel and Oscar. After the death of Tomas, Andrew tried to kill Rick and his group, and even seemed to try and avenge him by taking back the prison. It is unknown if they were friends before they were locked in the cafeteria together.
Axel has implied that he disliked Tomas and wasn't comfortable around him. Axel was glad that Oscar had his back whenever Tomas got angry at Axel or decided to blame him for something.
Oscar and Tomas weren't alike at all, as explained by Oscar in "Killer Within". It is mentioned by Axel that Oscar stood up for him whenever Tomas got angry at Axel or decided to blame him for something.
Despite not seeming to have any quarrels with the man and a somewhat neutral attitude towards him, Tomas did not have any problem brutally murdering Big Tiny after he was scratched by a walker.
- "If I see you out here, anywhere near our people, I'll kill you."
- —Rick threatening Tomas[src]
After discovering the prison survivors in a cafeteria, a conflict between the two groups immediately started. Rick would not allow Tomas and his group to reclaim their cell block, due to it being occupied by his group. Rick then told Tomas the prison belonged to him and his group, as they had taken out all the walkers occupying it. When the prisoners refused to leave, Rick agreed that he and his group would help them clear out a new cell block to live in, but warned Tomas that if he and his people came anywhere near his group, he would kill them. After witnessing Tomas brutally murder Big Tiny, Rick realized he was dangerous. Tomas tried to kill Rick twice in the prison's laundry room, prompting Rick to drive a machete into his head.