Cherubim

"A cyber cherub clattered in a clumsy search pattern around the scriptorium on metal wings. Such things were grotesque, techno-alchemy far removed from the purer machinery of his day. The madness of Mars had infected everything;

The cherub’s emerald eyes flashed at each word. The sensibilities of this age did not appeal to Guilliman. Hateful art for a hateful time;

The primarch watched it go back to its roost with critical eyes. The wings were more than adornment; from the sound of it, there was not enough lift in the gravity impeller to keep it aloft. The machines of this millennium were crude. The engineers among his brothers would probably have caught the thing in a net and rebuilt the motor; he was close to doing so himself. Either that, or tossing it out of an airlock into the void and replacing it with something less ghoulish."

– Big Bobby G, reviewing a Cherub in Dark Imperium

"Imperials are so fucking nasty, I swear to the gods..."

– Wide Ahriman, agreeing on Bobby's sentiments

Wild flying babies. Unfortunately trying to put a diaper on one of them is a painful and arduous task.

A particularly messed-up variant of a servitor/servo-skull (/tg/ isn't sure where these things should be categorize) is the cherub (plural: cherubim), which uses a vat-grown baby instead of a dead servant's skull as the base structure and therefore have much more in common with your garden variety servitors rather than simple robotic machines.

It sounds like something Slaanesh dreamed up, but apparently it's all the rage for higher-ups in the Ecclesiarchy to have little choirs of the things to sing hymns.

One member of the GW staff went to an extraordinary length in describing where they came from and what various purposes they are suited for. According to the history, they first turned up in M33 to celebrate the ascension of the Emperor to the Golden Throne, where the Adeptus Biologicus released 2000 cherubs into the Throne Chamber (one for each year of his enthronement) where they all flew up into the rafters to sing hymns and remain there still, being maintained by the Mechanicum, and presumably shitting on everything just like pigeons do. This act just serves to make The Emperor's torment greater, not just because of the Religious reasons, but because Cherubs are made from Babies.

While singing hymnals is certainly what Cherubim are most well-known for, they do have a number of other roles, since unlike servo-skulls they do have at least some level of intellect to be able to perform complicated tasks.

Goge Vandire had them installed EVERYWHERE during the Age of Apostasy, acting as mobile CCTV cameras so he could spy on everyone looking for sedition.

Some starships have Cherubim aeries installed to help out with menial everyday tasks, though this generally freaks out the common crew as having feral babies flying above your head is pretty poor for morale.

Guilliman is not a fan of them (see above quote). Neither is Magnus the Red. We can't blame them.

Types of Cherub

Other less documented roles include:

• Butler - Basically a house menial, attends to cleaning and serving things when expected.
• Crusader - Adorable teddy bear sized servitors in plate, as if being surrounded by armoured babies makes you appear more threatening.
• Custodian - Tattooed with Hexagrammatic Wards, these ones are trusted to carry proscribed artifacts.
• Foci - Psychically attuned to their masters, and can be used as psyber familiars.
• Gregori - Little dudes with freakishly large eyes, fitted with auspex scanners
• Harpy - Babies with blades attached to their feet, are almost always female and are used as combat pests.
• Incensor - Babies carting around fog machines. Sisters of Battle tend to use them to help refocus their faith.
• Love Angel - Cupid in 40k for people who like to be watched by cyborg-children while they do it (You wish I was kidding). They exude pheromones to heighten sexual attraction. How the fuck this has not gotten purged as Slaaneshi heresy is unknown.
• Reaper - Babies dressed in dark robes, come equipped with digi-weapons to remove people bothering their masters.
• Shining - these have refractor fields built into somewhere in their bodies. Not really useful to its master unless you send it somewhere for a different reason where it's likely to be destroyed.
• Squire - Babies with muscle augmentations, which can hilariously make them stronger than full grown adult humans. Their purpose is to hold whatever gets passed to them by their master.
• Stenographer - a much more discrete quill servitor, records everything said in its location.
• Swift - Much larger wings which allows them to generate more thrust and speed.
• Sycophant - Carries around a mirror to let you know how special you are.
• Tailor - fixes clothing handed to them using an onboard supply of thread.
• Weapons Loader - exactly what it says, tiny people trained to reload a weapon when it's given to them. Space Marine Devastator Squads in particular use these quite frequently (named as Armourium Cherub).

While some Cherubs can be manufactured to perform multiple roles, there is always a limit to how much a single servitor can be expected to carry out. Hence, you might find a pack of cherubs built as butlers to attend the care of a household, but also double up as harpies to chase off unwelcome guests.

Thus there is actually a second list of more complicated tasks that Cherubim might also be created to perform usually to the exclusion of anything else:

• Chorister - The typical singing Cherub that is well known across the Imperium. Probably more complicated because they need to know an extensive back-catalogue of songs to sing. Some also know how to play instruments and carry around incense burners.
• Generator - Essentially a flying force-field. These ones have massive, clunky power field generators built into their bodies.
• Grenadier - Dressed up like little soldiers, these ones carry bombs and set them up wherever ordered to by their masters.
• Healer - A medic, equipped with a variety of medicinal tools. Unlike a medical servo-skull, which are tools for 40k doctors and carry their kit where directed, these little critters can actually attend to wounds and simple illnesses on their own without prompting.
• Jailer - Floating interrogation tools, carrying psy-nulling manacles, shock collars and a variety of drugs. Basically your BDSM baby.
• Messenger - much more complex than messenger servo-skulls. Rather than hunting for a person based on likeness alone, they are equipped with pheromone sensors and can track a target by smell and deliver a cogitators worth of information. They are also always built as Swift Cherubs too for quick movement.
• Pariah - They can do it via cloning anyway due to blank souls not having troubles in cloned bodies, making Inquisitorial Agents and Culexus Assassins, so why not have an untouchable baby? Comes with a handy limiter to turn the field on and off.
• Sage - Carries archeotech relics that perform specific effects, because nothing says opulence like having feral flying midgets using your most fragile and expensive equipment for you.
• Seer - Blind cherubs that have somehow been Soul-bound to the Emperor, which must make them hellishly expensive/rare if this is the case. Their purpose though is to channel psychic backwash from perils of the warp from psychic masters.
• Spy - Little Ninja servitors often cloaked in Chameleoline, they have augmented lungs that allow them to resist airborne toxins, a sophisticated on-board suite of short ranged cyber senses for detecting poisons and they also have implanted multi-keys and know how to pick locks.

Nephilim

In quite possibly the most grimdark of grimdarkness, there is actually an upper category of Cherubim, referred to as Nephilim (which means Fallen).

While it is rumoured that rarely a tech-priest can create a master-crafted Cherub with a considerably higher intellect, the truth is that occasionally Cherubs are manufactured using ACTUAL BABIES rather than vat grown ones (perhaps too grimdark for mainstream GW, hence the article was labeled as "unofficial" with heavy emphasis on the inverted commas).

The difference is that vat-grown servitors have no developed central nervous system, which essentially makes them living vegetables until they are given a directive to follow. In the case of human-servitors, they already have a developed CNS and therefore are able to be trusted with multiple complicated tasks and actually use their initiative to figure out what needs doing.

Thankfully, it numbers the times that Nephilim have been made since they are regarded as extremely uncommon; only 22 times since M36 and each for personal reasons determined by the owner and not just for creating a "better" Cherub.

• One Nephil, "L", was a psyker of such power that it was impossible to transport her via Black Ship, so the Inquisition fixed her into an angelic lightning rod that served the inquisitor for 157 years until it was destroyed by a Daemonhost.
• Another case file was on Maya's World in 076.M41, where a certain Lord Torrington had his comatose son made into a Nephil rather than watch him die. Unfortunately, due to Imperial inheritance law, the Servitor was eventually named Duke and has been the head of the house ever since.