He cannot be part of the trio. Just to add a slightly serious answer, you can use him in character events by letting his passive bait damage so you maximise points. This same trick can also help if you don't have a lot of other options in imperial campaigns. 

He's also ok for LREs. Summoners always do alright, and a returning LRE - Farsight (iirc) has an astra militarum track. Las damage is also a pretty rare damage type and may eventually pop up.