Bonesinger

Bonesingers are Eldars'artisans, weapon crafter, architects, masons, IT technicians, janitors, coffee brewers, firefighters, yadda yadda yadda. They possess the unique ability to shape the Wraithbone, without which Eldars would be armless failures.

They pratically do never see combat, unless a Wraithlord breaks a leg or a Falcon's weapons go derp. Still, they managed to be in Dawn of War.