Many important characters in The Tempest appear in the first scene of the play. Sebastian is one of them. It already seems like he and Antonio are up to something, but the audience remains clueless until the play ends. Sebastian is the king’s brother who attempts a murder later on.
Sebastian is Alonso‘s brother. At first, it doesn’t seem like he may play any significant role. However, the audience may be surprised to find out that he has no good intentions. What makes it worse is that Sebastian is easy to manipulate. Therefore, his greed for more power finds its way out with Antonio’s help, who has experience in betraying in the past. They plot against the king and plan on murdering him while everyone’s asleep. It is not the noblest way to take someone’s life, but it fits Sebastian’s character. In fact, he is a coward. Alonso’s younger brother appears to have some doubts and almost back out of the assassination, but Antonio uses his persuasion skills to encourage him.
Fortunately, the king stays alive, and when the royal party awakes, the traitor duo has to come up with an explanation of why their swords are out. Sebastian is the one who covers them up with the story about lions they presumably heard. The last lines of this character show that he hasn’t learned anything. Being as arrogant and cowardly as at the beginning of the play, he proceeds to mock and make fun of Trinculo and Stephano. It seems like he does not see anything wrong with his behavior and actions.