Nurgling

"Who's a cute little plague beast? You are!" - Nurgle

Nurglings are the lesser daemons of Nurgle who are with affection referred to as 'Nurgle's little boils' by his worshipers and 'vile pusbags' and 'arrrrghh what the hell is that thing?!' by everyone else. Despite this, their models are alarmingly cute. They are born from the pustules and tumors that grow inside a Great Unclean One, although any stalwart follower of Nurgle is able to give birth to one of these through his own skin.

A Nurgling looks like a miniature version of Nurgle himself: a tiddly bloated humanoid critter, crawling with disease and difficult to look at (like all daemons). They rarely reach over a foot in height and as much in width. They are playful creatures, often demanding constant attention and frequently rough and tumble with each other. The Great Unclean Ones laugh at the antics of the Nurglings and pat them with affection and shower them with scraps of meat. They're sometimes eaten as snacks though-- not that this matters much, as they simply crawl back out of some open wound or another. Other worshipers of Nurgle are not so forgiving of the Nurglings; the Plaguebearers see them as irritating nuisances that get in the way and mess up their attempts at counting things (like for example, one counting how many drops of pus it takes to fill a pool might have to start over when a Nurgling decides to splash through it).

Individually, a Nurgling isn't physically powerful and not a threat in itself; it is the diseases that inhabit them that are the true threat. To let them touch you is to invite lethal pathogens inside your biosphere. Their combat strength is in numbers; Nurglings will often drown much tougher enemies in endless swarms that move like rivers underfoot of advancing Nurglish armies.

Just like most other pets in 40k and Warhammer Fantasy, Nurglings can and will willingly perform tricks. It is highly recommended to bring a Nurgling to a karaoke night, as its connection to the Warp and daemonic power could be used as a magnifier for your voice to turn into a magnificent wail. After the success that karaoke night will obviously be, make sure that your lovely voice did not attract any lonely daemonettes. The most lethal weapon against a Nurgling is a broom, the best tactic against a swarm is a good ol' fashioned flamethrower.

"Lords of Silence" has shown us that Death Guard rather jovially call them "Little Lords" and find them most amusing, even when they shit on their arm, and "Warhawk" shows even a blackhearted bastard like Typhus is affectionate towards the little guys.

Glitchlings

Oh, your bolter ain't working out for ya? Well ain't that a problem?

"Bite, bite, chew, chew, your gun won't work and I'm coming for you!"

– A rhyme chanted by a group of Glitchlings

Glitchlings are close relatives to the Nurglings, first reported in M32 after Perturabo made a pact with Nurgle to conquer the Forge World of Toil. Perturabo's ritual saw the machines rise up against the planet's ruling Tech-Priests as the Iron Warriors invaded. It was then that the Glitchlings appeared among the rambling cybernetic horrors. These buggers are distinguishable by their semi-mechanical appearance and the disruptive aura that surrounds them. They are known to fight beside any creature that has been infected by the Gellerpox plague.

Like gremlins, they cause machinery of all types to malfunction and fail in their presence and show a perverse amusement at the distress their victims show when their weapons fail at the worst possible time. The true purpose of the Glitchlings is to bring entropy and disease to machines just as Nurglings bring pestilence and disease to the organic.

Though their primary purpose is to disrupt technology, Glitchlings are also malicious creatures that will engage in battle with an enemy. Although no more formidable than a regular Nurgling, their touch is just as imbued with infection and disease.

Glitchlings first made their appearance in the Kill Team Rogue Trader expansion. On the tabletop, these daemonic munchkins have Disgustingly Resilient (albeit reduced in effectiveness because of Squishable, like Nurglings in vanilla 40k), and a 5+ invuln. Also causes a -1 penalty to hit them when targeted by ranged attacks. They are categorised as Combat, Scout and Zealot under Kill Team classification.