These are your most difficult adversaries. In the grand scheme of the rock-paper-scissors class system, they’re the paper to the devastator’s rock and will definitely smother you if you aren’t careful.
Their speed and abilities cover lots of ground, which when mixed with a stun on arrival and their close combat focus means they can exploit your weaknesses by ambushing you without warning, and then flank or get behind you with ease and inflict lots of damage in the one place you’re handicapped, hand-to-hand combat.
There are ways to deal with them though.
The first is the tried and tested "grenade and evade". You take an educated guess at where they’ll land (on you, most likely), throw a grenade at your feet and evade away (might be better off running). This will weaken the attacker and set them up for a few shots, another grenade, or being stomped or kicked.
The dev's stomp is useful for stunning attackers, allowing you the chance to follow up, but you must be ready. Too often, devs rely on the stomp to finish the job, and even upgraded, it rarely will work. You have to follow up with some gun fire or a kick to the chest.
In fact, the kick will progressively stun your foe if you get the right rhythm going, and it’s quite funny to boot. While the kick will do damage, its most important role again is to set up the killing blow of either the bolt pistol or a heavy weapon.
Really, the most important thing is to not let yourself be cornered and to not let the enemy make hand to hand contact in the first place. If you can retreat while firing do so, if they get too close, kick them, BUT FOR EMPEROR’S SAKE, REMEMBER:
Kicks go in the direction you hold down. So if you are pressing back, because you’re backing away while pressing kick, you will end up kicking the thin air behind you, while you get a chain axe in the back. This also mean that if you are being snuck up on however, that you can press back and kick and kick your assailant in the face before they can successfully assassinate you like the underhanded blagard they are.