Sun Wukong is a Faunus from the Kingdom of Vacuo, who later moved to Mistral.  He is the leader of Team SSSN.

In his first appearance, Sun is shown to be fun-loving and mischievous, with little regard for the law - stowing away on a ship, thanking the crew for the ride during his escape, throwing a banana peel in a detective's face and stealing apples. He has a lot of self-confidence, referring to himself as a "great stowaway". He also has a strong crush on Blake Belladonna.

In conversation, Sun is very laid-back and casual. This translates to his choice of clothing - he heavily dislikes wearing formal attire. He is also kind and patient. When first meeting Blake, he is willing to listen to her story and waiting for her to open up for nearly two days, bearing with her "small talk and weird looks". He is not afraid to give his opinion and has a dislike for those who regard themselves as "holier than thou" or "use force to get whatever they want", such as the White Fang.

Sun also seems to be willing to help others, regardless of whether he is asked or not, even if he barely knows them. In his second appearance, he goes out of his way to help Blake, whom he had just met and barely knew. This quality is further demonstrated when he readily volunteers to help Team RWBY with their investigation, despite both Blake and Ruby Rose  stating their opposition to his involvement.

He also does not like it when people dear to him have to risk their lives; he shows great opposition to Ruby and Weiss Schnee endangering themselves to search for Jaune Arc and Pyrrah Nikos during the Grimm attack on Beacon Academy. However, Sun himself is willing to put himself in harm's way for those he cares for.

In Volumes 4 and 5, Sun persistently remains at Blake's side and continues to try to help her in any way he can. He expresses wisdom in pointing out that Blake's friends want to fight for her, and that she should not try to distance her friends because she feels responsible for bringing harm to them. He begins to personally take Blake's campaign against the White Fang to heart, believing it's the right thing to do and wholeheartedly pursuing the same ends. In that respect, Blake believes Sun to be the embodiment of the word "earnest".