While this "challenge" seems to be made for malicious blades, it's very hard to survive long enough to actually get the trait, because it bocks berserker.
The technician tracking maps helped a lot in ambushing imps demons, and instant consumption of medkits was also very nice, but ultimately more health and longer berserk duration is much much better, and once you get berserker, your defence is so much better. Best proof is that after dozens of technician tries I won it in 2-3 marine attempts. At some points in this game I was actually thinking that I accidentally set it to lower difficulty.
Malicious blades is a good trait, but not so good in melee-only challenges. It's best if you can use a shotgun until you get it.
BTW, another tip if you want to attempt this: you are allowed to shoot any gun, as long as nothing dies while you're holding it. Best way to deal with demons (unless you are zerked) is to shoot them with a shotgun a couple of times and then finish them off with knife/fists. From my experience, as long as they are not in point-blank range, you can safely shoot at "wounded" pinkies. Take care not to kill anything else that might be standing behind the demons, though.
Another way is to lure them into acid pools (which you can prepare yourself with good barrel placement).
If you find a vault that's (based on sounds) filled with pinkies, I've found it best to open the vault using a barrel (close doors and shoot them to be able to push barrels through them), let the demons disperse, and then kill one at a time.
Oh, and if you know there's a pinky who you don't want to engage, don't leave any doors leaving to his room open. In case he begins to chase you, if you start running, you should be able get one step ahead after a few tiles, run behind a door and shut it to his face.