Tech priests are pretty common all over in regiments and in ships. Someone has to keep the lights on and the machines working.

Haolao could act as an intermediary between the PCs and the senior tech priests as he hasn't fully gone robot mode and is comparatively young for a tech priest (I can change his age). He would be there to provide another set of eyes on any given thing. During missions he could act as a support class, giving recon via servoskulls and scanners, dumb muscle in the form of servitors and a knowledge bank since I doubt any given guardsmen is going to be all that knowledgeable or worldly compared to a tech priest. He could even be a heavy weapons specialist, being able to lift all sorts of heavy things with mechanical assistance. Of course he'd also be around to fix machines and guns and set up anything that tech priests normally would have to do.

Again, I can change things about my character to better fit this.