Tristan is a very energetic and tenacious boy. He expresses no appreciation about the role of prince, instead preferring to defend his kingdom as a Holy Knight. Despite pretending to be a knight, he holds a great sense of justice and feels the need to protect his kingdom from anything threatening it, including his father and other Sins upon hearing how they were framed years ago yet didn't know how they were framed until learning from Gowther's "story". After learning about his parent's journey around Britannia and fighting the Ten Commandments, he desires to become the Seven Deadly Sins due to their heroics in saving the land from the Demon King and Cath Palug, showing that he has great respect and admiration for heroes.
On his tenth birthday, Tristan heard one of the maids talk about the Seven Deadly Sins meeting in the castle that same night. Ignoring the truth about them and only knowing that they were criminals who were once exiled from the kingdom, Tristan assumes that they intend to take control of Liones. He then runs off to call other children of the kingdom telling them that as a Holy Knight who protects the peace of Liones it is his duty to capture them.
When his friends do not take any of his words seriously, Tristan decides to go to the castle and ambush them on his own. There, he is surprised by Elizabeth who was looking for him, which worries Tristan for having been discovered by the Sins. Meliodas and the Sins introduce themselves, although everyone is friendly with him, Tristan is suspicious stating that he knows they intend to do a coup d'etat. Everyone takes it fun, even Meliodas jokes about acting like a villain to confuse his son.
Tristan is then taken outside where the entire kingdom has gathered to celebrate his birthday. Although Tristan insists that his father is the leader of some villains, Ban tells him that if so, the people of the kingdom would not admire him the way they do. Tristan sticks to his ideas by highlighting all of his father's bad habits. Gowther then uses his powers to give him a special gift: to show him the true story of the Seven Deadly Sins.
The next day, Tristan goes to a picnic with his parents. After a sword training session with Meliodas, he tells him that his future expands like heaven and that he does not have to become a king, which may be what he decides, even a Holy Knight. Tristan then says that he has already decided: he will be one of the Seven Deadly Sins.
Tristan has shown to possess above average combat skills, both barehanded and with a sword. Gowther claims he possesses an impressive Power Level for a boy of his age.
Meliodas is Tristan's father. At first Tristan considered him a short, irresponsible and alcoholic person who touches Elizabeth's bust every day, but after witnessing the real story of the Seven Deadly Sins from Gowther, he comes to respect him, wanting to become one of the Seven Deadly Sins.
Tristan seems to have a good relationship with his mother.
- Tristan was one of the more notable members of King Arthur's Knights of the Round Table. He was the son of King Meliodas and his first wife Elizabeth. He is well known for being an excellent archer with his bow Failnaught, and especially for his tragic romance with Iseult.