Design: Looks pretty cool for an island boy. And who doesn't love the bandana? Of course, how he travels through volcanoes, quicksand, and mountains in those shorts perplexes me.
Combat: Well, you have him for the entire game, so you'll have to get used to him at some point. He's very powerful, and his Techs are nothing to laugh at. Plus, he's White innate, so he's perfect for combating the major villains of the game. Oh, and let's not forget he gets the Mastermune (which is the strongest weapon in the game, right?), so that's a huge advantage. Serge kicks ass in battle, despite being balanced in some ways and not 'insanely strong' in any particular area (except maybe Strength?).
Oh, and he uses oars.
Tilt: Gets plenty of development for a silent protagonist. It's nice to see what happened in his past, involving his father and such. Lynx switches bodies with Serge later in the game, which I felt was a pretty interesting twist. It was funny to see Arni villagers hiding from Serge himself, and the eventual Dark Serge battles were neat. I'm counting those because it allows us to see Serge in a different way. He's certainly a unique protagonist, and we can see determination from him very often, despite being silent.
Final Grade: A