u/Glittering_Lab8098

My first guess would be that they’d specialize into burrowing underground to better attack the Necron’s tomb complexes, which need to be destroyed to stop the Necrons from constantly reanimating, either being permanently destroyed or forced to teleport to another tomb world/ship to be repaired. 

(Destroying anything capable of creating portals for other tomb worlds to send reinforcements also seems like a #1 priority.)