GOTTA GO FAST
He is a fast character. He is an IlluminaGee member. It didn't say he was, but it proved it. He is a friend of Geemina. He was sent to help in AGK & Ronald's dreams. He saved them from Siren Head.
Sanic is a man of Justice. When Luigi asked him to kill Toad, he told him it defeats the purpose of peace. He only kills villains. This proves even more that he is part of the IlluminaGee. It also seems that with justice, he may punish people. However, in the video, Toad does it for him. Toad punishes Luigi, and Sanic just tells Luigi "good luck Luigi".