Tom is one of the victims of the illness spread by Nimueh and her Afanc through the water system. Merlin uses a healing spell to cure him of the sickness and help Gwen in her desperate situation. But his quick recovery does not stay unnoticed and Gwen is accused of sorcery, when an enchanted item is found and Gwen has to face execution by Uther. Merlin, Arthur and Morgana save her by slaying the creature. Later he appears when Gwen is freed. Tom thanks Merlin and Morgana and is happily reunited with his daughter (The Mark of Nimueh).
Later Tom is working for Tauren, who uses magic to create gold (alchemy), which Tom does not know at the time. At the point in time Tom realises what Tauren is using him for, Arthur arrests Tom, while Tauren is able to escape, and Uther condemns Tom to death believing that Tom was conspiring with a sorcerer and practised magic himself. Morgana tells Uther that if he kills him she'll never forgive him. Later Gwen visits Tom in his cell, who tells her that he does not know Tauren was a sorcerer and that he just wanted Gwen happy but she explains that she is happy and she doesn't need something else. She promises to get him out before she leaves. Morgana, realising Tom's trial is merely a formality, gives Tom the key to escape.
However, he is discovered and surrounded by guards, who kill him on the spot and leaving Gwen an orphan. His corpse is seen being carried out by the guards and when Gwen sees this she is devastated. Morgana angrily watches this from her window as and angrily confronts Uther, which she is punished for. His death also drives Morgana to conspire with Tauren to murder Uther (To Kill the King).
According to Merlin, Tom was the most gentle soul he had ever met. As he has only appeared in two episodes, full knowledge of his personality is unknown, but he loved his daughter Guinevere and was determined to make her happy. Though, it was unknown what kind of relationship he had with his son Elyan it assumed that Tom loved him just as much as he did Gwen. Unfortunately his determination to make a better life for him and Gwen cost him his life when he was discovered working for Tauren even though he hadn't intended to commit treason.
According to Gaius, Tom was the finest blacksmith in the kingdom. He made the sword that would become Excalibur after it was imbued with the breath of Great Dragon. He also was strong enough to knock out a guard during his escape.
When Gwen and Elyan were both in Cenred's cells, they mentioned their father, Tom, and how Elyan didn't return when he died (The Castle of Fyrien).
When Guinevere was held trial, Uther assumed that she "enchanted" Arthur for revenge over the death of her father (Queen of Hearts).
When Arthur was suggesting who would betray him, he suggested Elyan, and said that he had reason to betray him because Arthur's father killed Elyan's father (A Servant of Two Masters).
- Tom forged the sword that would later become Excalibur. After his daughter, Gwen took it to help Merlin find a way to kill the wraith of the deceased Tristan de Bois, it was later thrown into the Lake of Avalon and would eventually end up embedded in a stone until its rightful owner, Gwen's husband Arthur pulls out it at the advice of Merlin. It is unknown if Tom ever found out that Gwen had taken it.
- Series 1
- Valiant (Mentioned only)
- The Mark of Nimueh
- A Remedy to Cure All Ills (Mentioned only)
- Excalibur (Mentioned only)
- To Kill the King
- Series 2
- The Witchfinder (Mentioned only)
- Series 3
- The Castle of Fyrien (Mentioned only)
- Queen of Hearts (Mentioned only)
- The Coming of Arthur: Part Two (Mentioned only)
- Series 4
- His Father's Son (Mentioned only)
- A Servant of Two Masters (Mentioned only)
- The Hunter's Heart (Mentioned only)
- Series 5
- The Dark Tower (Mentioned only)