So the Maquis included at least one known serial killer, Suder. This was a plot point in a couple of episodes. He was introduced, locked up, and died “heroically” fighting the Kazon in Basics.
Later on they introduced the Hirogen, an even less interesting threat force than the Kazon. They were shameless, uninteresting ripoffs of the Yautja, and the show suffered for their presence.
Let’s kill two birds with one stone. We have the wasted potential of having a serial killer on board, even if he was locked in his quarters and undergoing therapy with Tuvok to control his “kill seventeen people and stash the bodies in the crawlspace while dressed like a clown” urges. Then we have the pathetically boring Hirogen who were not helped with their obligatory Space Nazis episode (somehow made even worse by being a gorram holodeck episode ferfarksake).
Here’s how we do it:
The first encounter with the Hirogen lets one of them get on board using a shuttle (this is necessary). Considering the general incompetence of Voyager’s crew, this shouldn’t be difficult to arrange. Hirogen starts killing goldshirts, as every Next Gen threat force does, and eventually even Janeway realizes how screwed they are. Naturally, she assembles the command staff in the Magic Meeting room – because why not have all the most important members of the crew in one small room when there’s an assassin on board chewing through security personnel like pork rinds at a NASCAR event?
They start spitballing their usual stupid, really hyping up how scary the Hirogen are and how helpless the crew is in the face of these guys. Have Torres go on about how they’re so much more hardcore than Klingons, all that rot. Paris, the most competent person on the ship, is of course told to shush every time he has an idea – this is Voyager, where reason is considered blasphemy. We’re looking to kill some time here because the climax isn’t going to take long and we have 42 minutes of airtime.
After it looks like they’re well and truly skrued thanks to their refusal to be anything but idiots, have Chakotay chime in. “Hey, Captain, I know this is going to sound like crazy talk, but hear me out. Remember that serial killer I brought on board? How about you give me the keys to his cage?”
Cut to Janeway’s voice on the shipwide announcing general quarters as Chakotay opens Suder’s quarters. Suder saunters out with a smile on his lips, murder in his heart, and a big gorram knife in his hand. If it wasn’t to air on prime time network TV, I’d say also imply he was wearing naught but warpaint and an e-rection, but that would never fly on UPN. Then he says “this thing thinks he’s hunting, does he? We’ll see about that,” and cut to random terrified crew hiding in their rooms with phasers clutched in their hands. Have some distant sounds of the Hirogen’s tetryon beam gun going off, Suder making appropriately creepy sounds, and finally the Hirogen screaming.
Next we see the Hirogen’s shuttle drifting in space with its distress beacon active. Sitting in the pilot’s chair is the Hirogen’s dismembered corpse, neatly wrapped in plastic, Dexter style. Maybe we let other Hirogen board the shuttle and see what happened to their friend for a nice reaction shot.
Cut to Suder back in his quarters enjoying a steak that may or may not have come from the Hirogen. Maybe we see a Hirogen hide tacked to the wall to cure for Suder’s new boots.
Fade to black. Roll credits.