I wanted to know if I could create a theme for ' Trxilt '.
Sure, start by renaming the game to "Trxilt Pirates" or "Kingdom of Trxilt" or "Invaders from planet Trxilt" or "Ninjas of Trxlit". It's an imperative that the name draws you to the theme (because you want to attract players who want to play "pirates" or "ninjas" and the name would allow them to quickly find it).
Overall, "Trxilt" is a great name for an abstract, non themed game. And in your particular case I would not make a theme at all (theme is an opposite for an abstract game, actually, I think (could be wrong) the definition of an abstract game is a game without any particular theme).