That's because you are special. You are a good fighter. Even in Achaea a Tsol'aa knight had chances of staying alive if they did something right (healing). But as a Serenguard Merian, you aren't really taking advantage of the stat specialization, which you should Grab a tree and go Elfen, stop being a fish out of water.

Aeromancers- Trill

Knights- Trill and Lucidians

Guardians- Lucidians

And the Hallifax guardians should be the assassin/ninja/spy class

Meh, I know this is fairly late but it is definetly going to be both, the mesa sets precedence. There are both Trill and Lucidian warriors, and the leader of the mesa's warriors is a Lucidian. History shows us that the Trill were Aeromancers, and the ones who set up the ritual to attack the Eternal Flame were Lucidans, therefore the Guardians will be Lucidians. As for Lucidians not making good warriors, Trill have hollow bones, snapy-snapy? I'd rather have a brittle rock formation between me and the enemy than a pile of twigs.