Sir Lancelot is a friend of Merlin and a knight of Camelot.
Lancelot first met Merlin when he saved him from a Griffin and Merlin took him back to Camelot. When it was revealed only noblemen can join the Knights of Camelot, Merlin used his magic to create a seal of nobility. Merlin asks Gwen to provide clothes and armour so Lancelot looked like he was a nobleman. Lancelot became attracted to Gwen as soon as he met her and insisted on calling her 'My Lady' despite her telling him she wasn't a noble so shouldn't be addressed that way. He asked Merlin what kind of relationship he has with Gwen and seemed pleased when Merlin said they were just friends. He later told Arthur that he thought she was beautiful. Lancelot tried out for the knights and, although at first Arthur is unimpressed, he quickly identified that Lancelot has potential and accepted him into the knights of Camelot.
However when Uther asked Geoffrey of Monmouth to check the seal of nobility it was revealed to be a forgery and Lancelot was thrown in prison. Arthur, however, let him out and told him to leave Camelot and never return. Lancelot decided to fight the Griffin as he felt he had a duty to do so.
Before leaving to fight the Griffin he visited Gwen's home as he needed armour. She asked him not to leave but he insisted it was his duty, knight or not.
When the Griffin attacked again Arthur and the other knights were nearly all killed. Lancelot tried to kill the Griffin but it was only when Merlin enchanted his lance that the Griffin was killed. Arthur then appealed to Uther to reinstate Lancelot as a knight, thinking it was Lancelot who killed the Griffin.
Lancelot revealed to Merlin that he knew he was a magician and promised to keep his secret, however he also said he could not stay and take credit for killing the Griffin when it was really Merlin. He announce to Uther and Arthur that he intended to leave in order to redeem himself for lying to them. (Lancelot)
Lancelot traveled around after leaving Camelot and eventually started to earn a living by fighting for others entertainment, believing his life had become meaningless. He was working in a fighting ring run by a group of bandits when he saw Gwen had been kidnapped. The bandits had mistaken her for Morgana and were holding her for ransom. Realizing Gwen's life would be in danger if her true identity was discovered, Lancelot worked to free her, giving Lancelot a reason to live again. They shared a kiss and their feelings for each other were rekindled. However, when they tried to escape, they were captured and set to be executed. But they were saved by Arthur and Merlin, who had come to rescue Gwen.
While returning to Camelot, both Arthur and Gwen went out of their way to appear indifferent to each other. Lancelot was not fooled by this and quickly realised that they had strong unspoken feelings for each other, Merlin later confirmed this and although he had realised his own feelings for Gwen, Lancelot decided he wouldn't risk coming between her and Arthur. He left once again, asking Merlin to tell Gwen that while they weren't meant to be, she had changed his life. (Lancelot and Guinevere)
After Camelot fell to Morgana, Merlin sent word to him for help. Along with his friend Percival he saved them from Morgana's knights, and went with them to an ancient Castle. Within the Castle he was knighted by Arthur. Together with Merlin, they snuck into the tower, to break the enchantment, while the other's went to save the other knights and Uther. Although he was wounded during the final fight, he survived, and later went with the other new knights to get Guinevere. (The Coming of Arthur: Part Two)
It is likely while Lancelot is a knight of Camelot he will have a hard time dealing with Arthur and Gwens relationship.
Lancelot has a very strong sense of right and wrong. He was never comfortable with the idea of lying about his social status in order to qualify for knighthood. He also refused to take the credit for another's work, as he refused to do so when Merlin killed the Griffin and everyone thought he had. Lancelot was polite and respectful towards people higher ranked than himself even if they treated him unfairly.
During his duel with Arthur, Lancelot defeated the prince through trickery rather than skill. However in a real battle a warrior would need every advantage they could get and earlier in the episode Arthur believed that Lancelot was not ready for a real battle. Therefore Arthur accepted his defeat and allowed Lancelot to join the Knights of Camelot.
Lancelot is willing to risk his own life to save the people he cares about. He developed feelings for Guinevere as soon as he met her but despite his feelings for her he left so he wouldn't come between her and Arthur. This showed that he was very selfless.
Lancelot was a highly skilled swordsman and one of the very few who was able to fight Arthur as an equal and defeated him during their duel. It should be noted however that he defeated Arthur through trickery rather than skill. (Lancelot) Like Arthur he was capable of defending himself against numerous opponents at once defeating several of Hengist's bandits before finally being subdued. When he and Merlin went to search for the Cup of Life he fought against numerous immortal knights and drove them into the path of Excalibur, which was being weilded by Merlin, resulting in the knights defeat. Hengist was impressed by Lancelot's combat prowess noting that he was a skilful warrior. (Lancelot and Guinevere)
In addition to being a formidable opponent with a sword, Lancelot was skilled with a lance using it to slay a griffin that attacked Camelot. However his lance was made more powerful by Merlin's magic and Lancelot claimed that it was Merlin, not he, that had killed the griffin
|Kingdom of Camelot|
| Queen: Guinevere Pendragon|
Court Physician: Gaius
Keeper of the Royal Library: Geoffrey of Monmouth
Knights: Sir Leon • Sir Percival • Sir Brennis • Sir Cador • Sir Geraint
Other Allies: Merlin • Annis • Odin • Rodor • Mithian • Godwyn • Bayard • Elena • Alined • The Diamair • Vivian • Olaf
Former Allies: Morgana Pendragon † • Nimueh † • Cedric † ? • Cornelius Sigan † • Tristan de Bois † • Lady Catrina † • Edwin Muirden † • Uther Pendragon † • Agravaine de Bois †• Sefa• Mordred †