[@Hael] I would imagine the Mur-Po as being the most bitter rivals of almost everyone, but especially the Xim. 

Also I should clarify the bioships thing. They're technically not piloted; rather, they ("they" being a species of basically giant flying whales that were engineered from one that lives on the Mur-Po's home world), are transported in vast carrier ships wherein they are held in stasis, outfitted with cybernetic implants and their thermonuclear payloads, and slowly driven insane. A "pilot" (usually a thrall of the four-arm caste) introduces a destination, and the now insane whale-ship is basically set free to assume its rampage. 

It's still considered a rather dangerous offshoot of the same technology which is used for sublight transport (another genetic mutation of the animals which were ridden as mounts by the Mur-Po for millenia before the advent of their spacefaring age) in which the animal's metabolic processes are utilized to sustain the life support systems. 

Oh also they look like this sans female face

[hider][IMG]http://i730.photobucket.com/albums/ww305/Khaosn95/1459351730370.jpg[/IMG][/hider]

The Mur-Po also of course use more recent mechanical technologies to conduct travel and warfare but these are a relatively recent adoption compared to some of the other spacefaring nations. 

At least I think, I'm still finetuning the details.