The second PE for the two "Lows" I'll be discussing from the Red Dwarf episode "Demons & Angels".
What's the work?
Red Dwarf is a sci fi sitcom series owned by the BBC and Dave which follows the misadventures of Dave Lister the last human alive, Arnold Rimmer a hologram of his frenemy and roommate, The Cat a man who evolved from cats and Kryten a mechanoid who the crew rescued from his own ruined ship.
Who is he?
Low Cat is the dark alternate counterpart to the series tritagonist The Cat. Being essentially the exact same person as him but with none of his good qualities.
What has he done?
Low Cat was created after a device called the Triplicator split the Red Dwarf crew and vessel itself into three; the main crew, the Highs (versions of the crew with all of their best qualities) and the Lows (members of the crew with all of their worst qualities).
Before even showing up on screen he helps Low Lister kill both the High Cat and High Kryten by throwing a grenade at them after Low Lister killed the duo, he then begins savagely eating what's left of them before joining his fellow Lows in pursuing the main Lister, eventually cornering him in the cargo decks and taking him to the drive room with his allies.
With the rest of the Lows, Low Cat helps in the tormenting of the main Lister specifically suggesting that they make him walk to a supply cabinet and squeeze his face into the door before making him burn his crotch with boiling water with Low Cat then using the empty kettle to burn his own face for laughs, he also mockingly eggs the controlled main Lister on when the latter is forced into eating a live tarantula under his controlled state. Following this he happily joins in with the Lows' plan to get the main Lister to kill the remaining High and main incarnations of the Red Dwarf crews in his controlled state so the Low crew can steal Red Dwarf for themselves. He is last scene laughing manically at the sight of the final two highs getting killed before headbutting the low Kryten.
Low Cat then died after being abandoned by Low Lister with the rest of the crew once their ship had vanished from existence.
As was said on the Low Lister proposal many of the show's antagonists are far too powerful and have much more screentime in comparison to Low Cat who has a measly five or so minutes. In spite of his limited screentime however Low Cat manages to do something horrifying even in Red Dwarf context, cannibalism via eating his own alternate self High Cat, and above that he also is one of the only two Lows alongside Low Lister with a genuine body count, having been responsible for the deaths of two characters while also being an accessory to the murders of High Rimmer and High Lister through the body control implant placed on Lister.
Overall in spite of his limited screentime and power levels Low Cat manages to be a fairly horrible and nightmarish character, only rivalled in terms of heinousness fairly by Low Lister who was given more focus and screen-time.
Like Low Lister he seems to get along with the other Lows however it's moreso out of shared sadism as opposed to genuine comradery.
Low Cat being part of the same entity of The Cat means he does indeed have moral agency, only having none of the good qualities of his true self while acknowledging they still do exist.
Honestly even though he's a fairly minor and unimportant character he definitely is bad enough to qualify, certainly counting as one of the more vicious villains from Red Dwarf's TV form anyway, overall I'd say he's a weak yes for managing to have a signifcant and bad impact in spite of his mostly limited screen time.