User blog comment:Zathronas/Analysis by an author: volume 2 trailer part 2/@comment-25148977-20140708015857

It is also possible that Sun's team may be named after the solar system. Sun, Neptune, I've seen fan-names calling the red haired guy Mars, and maybe Terra or Venus for the last guy.

I doubt that he's a traitor considering that it's such a flimsy connection. It'd be the same as saying that Emerald will switch to Ruby's side because both of their names are gems.