Introduced by Kotobukiya to fill in the Mecha Musume void left in the market after Konami stopped further production of Busou Shinki, the FA Girls are also an attempt to make the original series Frame Arms mechs more accessible and appealing by turning the robots into cuter Robot Girls.
In a fashion rather like the Shinki, FA Girls have a lot of articulation and a modular pegs/parts system that leverages Kotobukiya's universal Mobile Support Goods (MSG) accessories for their model kits and action figures. However, unlike shinki and more like traditional Gunpla and other model kits, you do need to assemble the girls by detaching their parts from plastic runners and putting them together. The trade-off is a reduction in cost which makes the Frame Arms Girls kits less expensive (and more easily collectible) than Busou Shinki.
Anime previews for FA Girls were released over the turning of the calendar from 2016 to 2017, as Kotobukiya was working on an anime series to promote the line. Here's a trailer for it.
A manga about these girls, Frame Arms Girls: Lab Days, was also produced starting in early 2017, which covers the life of a bunch of FA girls living in a Kotobukiya research lab.
The anime adaptation started airing in early April as part of the Spring 2017 Anime lineup, and ran for 12 episodes. In it, a young lady named Ao Gennai gets introduced to the world of cute little robot girls as a result of her father signing her up for a monetized review/research program with Frame Advance (the Fictional Counterpart to Kotobukiya), which also conveniently frees her up from having to hunt for a part-time job in order to earn a little extra pocket money. The Blu-Ray release for the anime is in 4 volumes (3 episodes each), with exclusive new model kits of the girls (volume 1 has no-armor Gourai, volume 2 has no-armor Stylet, volume 3 has Anime Colours Baselard, and volume 4 has Gourai KAI) included with each.
Kotobukiya have chibi versions of the FA Girls reimagined as Cu-Poche jointed chibi action figures. As of the end of 2018, Gourai (KAI), Stylet, Baselard, Materia, Jinrai and Architect have poches of themselves, with Hresvelgr's planned for a 2019 release. They have also announced plans for crossover Frame Arms Girls from other franchises with the Cross Frame girls, the first two known such girls being GaoGaiGar and Sylphy from the Desktop Army series.
Desktop Army, too, has created their own takes on the Girls at near 1/18 scale. Gourai, Baselard, Jinrai, and Innocentia are on the shelves, and Hresvelgr and Stylet have been shown to be in prototype design phase. in 2019, Kotobukiya announced the use of their 1/24 Hexa Gear Governator pilot figure chassis as a new size form factor for FA Girls, with Gourai and Stylet being made at "Hand-Size" class even tinier than her regular figure.
Compare them to their duelling sister line, Megami Device.
Tropes demonstrated by the Frame Arms Girls as a whole:
- Art Evolution: The series style has evolved beyond the Fumikane-inspired Architect-derivative FA Girls with more unusual and exotic FA Girls appearing in the lineup after Baselard and Hresvelgr.
- Badass Adorable: Well yeah, these girls are sweethearts and are loaded for intense combat.
- Barbie Doll Anatomy: Just like their Shinki predecessors, they lack certain female attributes.
- Chainsaw Good: MSG Kit Dynamic Chainsaw - it has a fully articulated belt made of linked individual teeth, comes with a spring-powered windup motor, and can be outfitted with the battery-powered Gimmick Kit Motor. Of course, the tiny polystrene chainsaw teeth are both too blunt and too soft to really be much of a danger to your fingers (unless you get pinched between the teeth due to carelessness).
- Cute Machines: Just like Shinki and the Megami Device girls, they are adorable.
- Dangerously Short Skirt: Several of the FA girls have one.
- Distaff Counterpart: The girls are such for the original Frame Arms mecha.
- Does This Remind You of Anything?: FA Girls seem to react rather interestingly to having their charging cables plugged into their back.
- As shown in episode 1 of the anime, Gourai has a reaction to having her charger plugged into her, her mouth going 'O'-shaped for a moment as she squeals, much to Ao's surprise. In episode 2, Stylet blushes at the thought of Charger-kun "punishment" involving the charging cable, complete with rose-tint and suggestive sounds.
- In chapter 3 of Lab Days, Stylet squeals out loudly when Gourai quietly sticks the charging plug into her back, and tells her "not to jam it in without warning" in a fashion that could be taken out of context. She gets angry when Gourai does it again in chapter 4 and returns the favor - Gourai's reaction is not shown on-panel.
- Emergency Weapon: All FA girls derived from the Architect chassis (except Innocentia, Materia and Letizia) ship with a simple combat knife and a holster/sheathe for it that plugs into the 3mm sockets on their bodies.
- Fanservice: Some of the FA girls, like Gourai and Stylet, actually come with decals to decorate their underwear and make it look more like panties, with your choice of striped or lace/satin.
- Fun with Acronyms: Overlapping with Unfortunate Names, the Frame Arms Girls got acronymized by some of the fandom into FAGs. Several of the creators have requested for them to be referred to as F.A. Girls — however, when the name of the anime's production committee and the URL of the official website are written as "FAGirl", this just leads to the fandom reading it as "fag in real life".
- Gatling Good: In addition to Stylet's underarm-mounted gatling gun, there are two other kinds of MSG weapon kit gatling guns. These other guns are larger and can be motorized with the battery-powered MSG Gimmick Kit motor, and one of them comes out of the box with a simple wind-up spring motor.
- Ikea Weaponry: As a result of the Shinki-style customizable weapons and armor and the Mobile Support Goods, FA Girls can take advantage of amusingly over-engineered frankenguns (and frankenswords).
- Mecha Musume: Very much so. Gourai has tank treads in her feet, Stylet bristles with wings and flight control surfaces, and Hresvelgr has a 'visor' built in.
- Powered Armor: Their combat armor and rigging gives the impression of such, and are portrayed accordingly in the OVA and the Lab Days manga. At a larger scale, Kotobukiya has made Gigantic Arms suits for the girls, as well as made another toyline, the Hexa Gear series, with beast-mechs that transform into vehicles, fully compatible with FA Girls as transformable armored shells (as demonstrated by Architect here).
- She's Got Legs: As Materia, Baselard, Hresvelgr, and Innocentia demonstrate, without armor FA Girls have long and shapely legs.
- Small Girl, Big Gun: With some of the BFG style weapons the girls come with, they invoke this motif. You can help strengthen it with MSG series weapons.
- Stripperiffic: Materia, Innocentia, and Jinrai, with the "second generation" style hip and waist construction, have very skimpy underpants that are very thonglike. Gourai, Stylet, and Architect have short skirts that don't really hide their panties. Magatsuki and Durga I have armor cut such that it offers zero coverage for their butts, and their under-armor is styled to be lingerie.
- The Stoic: Thanks to Humida's preferences, many of the early FA Girls shipped with a neutral-expression faceplate.
- Theme Naming: Inherited from the mainline Frame Arms mecha (such as Durga and Rapier), several of the girls are named after weapons (Stylet is a mis-spelling of stiletto, Baselard, and Zelfikar/Zulfiqar, all of whom are named for bladed weapons).
- This Is a Drill: The MSG weapon kit for the Vortex Driver, fully usable by the girls. It features three different drill bits (a long, narrow 'normal' hole-boring bit, a flower-like serrated bit with bladed petals, and a stereotypical conical drillhead bit), and can be motorized with a battery-powered Gimmick Kit that runs on small LR44 batteries.
Tropes demonstrated in the Lab Days manga:
- Ace Custom: Unlike the restricted-intelligence mass production FA Girls of the previous generation, the protagonists are research models with more advanced 'unlocked' learning capabilities.
- Curb-Stomp Battle: Hresvelgr challenges Gourai to a quick spar in Chapter 1 of Lab Days and overwhelms her with experience, speed and strength - her first strike does more than half of Gourai's simulated lifebar in damage.
- Failed a Spot Check: Stylet doesn't notice a sticker Baselard planted on her while she was talking to Gourai in Chapter 3.
- Ghost Story: In chapter 3 of Lab Days, Baselard tells Gourai and Stylet one about some mysterious sounds she heard in the corridor at night, as well as a strange white figure that was wandering around. Stylet doesn't appreciate being spooked.
- Hilarity Ensues: Stylet insists on bringing Gourai over to meet the newly-arrived Baselard. Cue Stylet struggling to hoist Gourai and fly over to Baselard's cubicle.
- Improvised Weapon: In Chapter 6, the Black Materia uses a bolas made from hair decorations and an elastic band to try and catch Hresvelgr, who was wandering around the lab without permission. She ends up catching Stylet instead.
- I'm Taking Her Home with Me!: In Chapter 5, the Twins try to carry Gourai off after being quite taken with her cuteness and innocence.
- Reality Ensues:
- In chapters 1 and 2, Hresvelgr's eagerness to fight coupled with her willingly giving Gourai a handicap in battery stamina by not recharging after beating Stylet means she ends up falling asleep from battery power exhaustion after defeating Gourai.
- In chapter 3, Stylet's jetpack wasn't really designed for her to lift more than her own bodyweight plus some weapons, so naturally she has issues picking up and carrying the heavily-armored Gourai.
- In Chapter 4, it is revealed that the flight-oriented FA Girls Stylet and Baselard are too lightweight to move effectively with Gourai's heavy tanklike armor.
- In Chapter 6, it is revealed that Hresvelgr's rambunctious and naughty nature means that she didn't get permission to wander around as freely as the other girls, as the Materia twins demonstrate by arresting her for sneaking around behind her researcher's backs. It's also shown that Toda's suggestions to give Jinrai a "bold and heroic nature" ended up making the FA Girl into a samurai/ninja chuuni.
- Chapter 7 shows that putting the AS systems and FA Girl code into the Architect AI turned her into a full-fledged Frame Arms Girl, who ends up desiring a body and Master (parental figure) of her own.
- Chapter 8 shows that pushing the envelope on Hresvelgr's development to make her the most powerful FA Girl in combat also upsets Competitive Balance, making her far too strong for a small in-house tournament.
- Running Gag:
- Gourai j-j-jams the charging cable into Stylet with little-to-no warning twice. She gets angry the second time and returns the favour to Gourai.
- Baselard festooning things with stickers, such as her Charger◊, Stylet's jetpack, and an equipment case.
- Secret Test of Character: Fujisaki, Baselard's Meister, devises a simple test to see how much FA Girls can learn in chapter 4, by having her colleague Satou challenge them to assemble one of Baselard's weapon kits.
- Super Prototype: Compared to the restricted-intelligence FA Girls of the previous generation, the protagonists who are of the newest AS-equipped generation are much more intelligent, autonomous, and quite a bit stronger.