As a note. I consider the novels and the manga/anime to be three seperate universes. However, the fact that Tessa started crushing because she lost someone is no reason to disregard her feelings. Sosuke has saved her life a dozen times over since then, has shown her compassion, and he's also been her friend.
Sosuke can measure his friends on barely two hands now. Melissa, Tessa, Kainlin, Shinji, Tessa, Eric, and Kaname
Tessa I think can do it on one hand. Sosuke, Kaname (I think she's now her best friend), Melissa, and her commanders
It's weird but I think Tessa's loneliness is very compelling and really something that I want to see addressed. Chidori, whom I love, is able to have any boy she wants I'm sure but poor Tessa is stuck on a submarine of people she can't relate to. Sosuke shares the same isolated existence she does though and I like the idea of them 'comforting' each other.
Besides, what's wrong with Sosuke being a lifer? He's good at being in the military and its not like Hero Yui where his life is hell. He enjoys it even as he could do well to have a little more civilian time off.
I just want Tessa and Sosuke to have a Mirthil Wedding with a Mirthil Chaplin and have Mirthil babies.
I see the Tessa relationship as like Zechs/Noin really from Gundam wing while Kaname is the Relena to his Hero Yui. AND WE KNOW WHO ENDED UP WITH WHO
I don't underestimate the point that Kaname has done alot for him but frankly Kainlin is probably who messed up Sosuke's mind. I also think that again....she's more a friend than a lover. I just don't see any attraction between them really.
(The kiss in the train station was a dream sequence)
Plus, Sosuke sailed off with Tessa too on that sub
