The Duel between Arthur and Kilgharrah occurred during the Razing of Camelot when Kilgharrah attacked Camelot as revenge for his imprisonment by Uther and the near-extinction of the Dragons.

After Kilgharrah burnt down many parts of the Kingdom, killing many innocent people in the process, Arthur and Merlin went to find the last Dragonlord Balinor, who was killed during an ambush by King Cenred's soldiers. Arthur, unaware that the Dragonlord gift had been passed on from Balinor to Merlin, chose to face Kilgharrah himself in the woods along with some Knights of Camelot. Kilgharrah then arrived and easily defeated the Knights, killing many of them (except for Sir Leon) before facing Arthur.

The duel began when Arthur grabbed a spear and looked at Kilgharrah for a moment until Kilgharrah breathed fire at him. Arthur narrowly dodged the attack and impaled Kilgharrah with the spear which only wounded him slightly. Enraged by this, Kilgharrah struck Arthur with his paw, knocking him unconscious. Kilgharrah was only stopped when Merlin used his new Dragonlord power to force Kilgharrah out of Camelot.

Victory: Kilgharrah

Series 1: Merlin vs. ArthurArthur vs. ValiantMerlin vs. Edwin MuirdenSir Owain vs. Tristan de BoisSir Pellinore vs. Tristan de BoisUther vs. Tristan de BoisArthur vs. EvanMerlin vs. TaurenMerlin vs. KilgharrahMerlin vs. Nimueh
Series 2: Merlin vs. JonasArthur vs. MorgauseArthur vs UtherOlaf vs. ArthurArthur vs. Kilgharrah
Series 3: Merlin vs. MorganaMerlin vs. the GoblinMerlin vs. the Sidhe elderGilli vs. NollarUther vs. GilliMorgause vs. Merlin & Gaius
Series 4: Showdown with MorganaUther vs. The GleemanArthur vs. DeríanEmrys vs. the Knights of the Round TableEmrys vs. MorganaArthur vs. Sir LancelotArthur vs. Sir ElyanArthur vs. HeliosGuinevere vs. Morgana
Series 5: Arthur vs. Odin
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