King Kay

  After Sir Kay became the king, he killed all the loyal knights just because they can't sweet-talk as well as the other untruthful knights. Sir Kay killed Arthur to prevent him from causing any trouble, and keeping the truth: that Arthur is the true heir of King Uther, from everyone. He also went to kill Merlin, in fear of him revealing the truth.  Kay tried, but failed, because Merlin was too strong and Merlin stopped him and banished him from England. Merlin was very sad that people are so evil, so he casted a spell to make people wise and good-hearted again, and he became the king.