As the latest entry in one of Japan's longest running franchises, it comes as no surprise that The Witch from Mercury is not shy about referencing what came before.
- Gundam Aerial combines elements of multiple mobile suits from previous Gundam series. The thin waist and feet with a tall heel and cylindrical joint evoke the Gundam frames of Mobile Suit Gundam: Iron-Blooded Orphans. The various yellow pointed vents throughout the legs and back evoke the Vagan suits, especially the Gundam Legilis, from Mobile Suit Gundam AGE. The dark, semi-transparent panels meanwhile evoke the G-Self from Gundam: Reconguista in G. The sleek, rounded head resembles the G-Self but also the Gundam Exia from Mobile Suit Gundam 00. And the glowing red frame underneath evokes the eponymous Unicorn Gundam from Mobile Suit Gundam Unicorn. It also has some nods to the RX-78-2 Gundam from all the way back in Mobile Suit Gundam, having a pair of projections out of its back resembling its Beam Saber hilts, as well as having a beam rifle resembling a more angular version of the RX-78-2's and a shield as its most obvious armaments.
- Gundam Aerial Rebuild has similarities to the GP01-Fb from Mobile Suit Gundam 0083: Stardust Memory, such as having additional thrusters, armor, and the upgrade and repairs being done at the same time after its initial form got heavily damaged in a previous combat. It also has a mouthpiece with single vent, a rarely used Gundam face design that is only seen in less than a handful of Gundams such as Bolt Gundam from Mobile Fighter G Gundam, Raigo Gundam from Gundam SEED Frame Astrays, and Gundam G-First from Gundam U.C. 0096: Last Sun.
- Witch From Mercury has some similarities with Mobile Suit Gundam École du Ciel such as having a female protagonist, a school setting (at least in the beginning), and the characters singing "Happy Birthday to You" as many people are being killed in a battle. Even both works' lead Gundams: the Aerial and the Le Cygne, share some similarities too, such as being equipped with a large shield with multiple functions.
- "Happy Birthday" was also used at the end of the Space Runaway Ideon movie (created by Yoshiyuki Tomino)
- The scene in the prologue when Gundam Lfrith destroys some mooks is very similar to the first battle scene in Mobile Suit Gundam Unicorn. From the shot of the HUD of both the Kshatriya and the Lfrith as they lock on the targets, to the way the first two enemies are destroyed by Attack Drones, to how the third enemy dodges the drones and has to be killed with a different weapon.
- Duels are won by destroying your opponent's mobile suit's antenna, but as Guel demonstrates in the first on-screen duel, destroying the rest of the head together with it is acceptable, like in Mobile Fighter G Gundam.
- Due to the rule about mobile suit antennas, the regular Dilanza (essentially this season's Zaku Expy) will still have a head fin, albeit a modest one similar to the Johnny Ridden Zaku fin.
- The logos for the Benerrit Group's major mobile suit manufacturers are similar to those of factions from previous series: Peil Technologies has the Titans' eagle (not to mention the Gundam Pharact using the Titans' color scheme), Jeturk Heavy Industries uses a lion like OZ, and Grassley Defense Systems uses a snake like Serpent's Tail.
- Almost as a literal gag, in the AS timeline, Lagrange Point colonies are referred to as 'Fronts', while in the Original UC timeline they were 'Sides'.
- Suletta's birth year is in A.S. 105. 105 is the Arc Number of Mobile Suit Gundam: Hathaway's Flash, such as the year when its story took place, the serial number of its lead Mobile Suit, the Xi Gundam, and some of its movie's advertisements uses it for promotional purposes.
- The diamond shapes of each side of Suletta's hairband, along with the cutout notch between the diamonds, resembles Char's domino mask. Fans quickly noticed and lead to variations on this image
. - The CEOs of Peil refer to Elan as "Enhanced Person Number Four". Though officially translated "Cyber-Newtype", the Universal Century term in Japanese literally means "Enhanced Human". The first one featured, in Mobile Suit Zeta Gundam, was called Four Murasame. Extra meaningful because, as mentioned above, Peil Technologies has a logo similar to the one used by the Titans, the group who employed Cyber-Newtypes in Zeta. Elan's remark on his "borrowed" face also brings to mind later Cyber-Newtype characters which include genetic clones (Mobile Suit Gundam ZZ) and one who was surgically altered to take on the appearance of another person (Mobile Suit Gundam Unicorn).
- In episode 9, Chuchu has to connect to two more mechs to boost her beam rifle for a super-long-range shot. This tactic has been used several times in Gundam, most notably with the Methuss connecting to the Hyaku-Shiki's large particle cannon.
- In episode 11, when Suletta is on the verge of an emotional breakdown thinking that Miorine doesn't need her, Miorine gives Suletta a much needed blow to the head to get her to shut up and focus, much like a certain Bright Slap.
- Norea Du Noc has a huge resemblance to Kamille Bidan. Her Lfrith Thorn's face also looks like the Zeta Gundam's (except the former's chin is red-colored) and is also equipped with a BFG, just like the latter and its Hyper Mega Launcher. Meanwhile, Sophie Pulone, with her curly brown hair and happy attitude, gives her a resemblance to Judau Ashta (though Judau isn't Ax-Crazy).
- Norea's similarities to Kamille are even made more obvious in Episode 13; she briefly pilots the Gundam Pharact and bullies someone on foot (in this case, Nika), just like Kamille doing the same thing to a Titans officer while piloting a dark-colored Gundam (the Gundam Mk-II in Titans' colors).
- Aerial Rebuild grappling the Lfrith Ur and using its superior thrust to force it out of the hangar and into space is near-identical to the Unicorn overpowering the Kshatriya.
- Aerial Rebuild's posture when using the full bit-on beam cannon calls to mind the Hyaku-Shiki using the Mega Bazooka Launcher or Wing Zero using its Twin Buster Rifle.
- The Gundvolvas that debut in Episode 14 are functionally identical to the G-Bits from After War Gundam X, being unmanned, remote-controlled Mobile Suits activated by a system that connects the mind of the pilot with their own Mobile Suit.
- Perhaps because of the nature of a battle royale-esque Rumble Ring, but Elan swapping out his Pharact's sniper rifle for twin handguns brings to mind the transition from Dynames to Cherudim in Mobile Suit Gundam 00. And similarly, this is possibly a matter of preference for a new pilot taking over the role of an identical predecessor.
- The way the handguns combine into a larger beam rifle, is similar to that of Strike Freedom's combined long beam rifle.
- Continuing his resemblance to Lyle Dylandy, in episode 20, Elan #5 is forced to watch as Norea is killed in front of him when her cockpit is shot by a Dominicus sniper, much like how Lyle was forced to watch Anew die to Setsuna.
- Guel experiences a PTSD attack prior to and during his third duel against Suletta, similar to Jamil Neate's cockpit phobia at the beginning of his home series.
- The Children of the Coven seem like a riff on Glemy Toto's Newtype Corps in Mobile Suit Gundam ZZ. Both are a group of clones of a young girl uniquely capable of operating mobile suits. The twist is that only one of the Coven's children is a biological clone, as the rest are Virtual Ghosts.
- Episode 19 features a peaceful protest turned violent due to a False Flag Operation just like the Dort Arc of Mobile Suit Gundam: Iron-Blooded Orphans.
- In Episode 21, Kenanji mentions being unable to identify the Lfrith Thorn's pilot, which mirrors the Earth Federation being unable to identify the pilot of the Zaku II Kai that damaged the Gundam ALEX. The Lfrith Thorn is severely damaged but remained mostly intact, while Norea's body is vaporized by the beam shot that punctured the cockpit; by comparison, the Zaku II Kai is fully destroyed and Bernie's remains are reduced to something similar to a "pile of hamburgers".
- In the same episode, Gundam Caliburn's existence as a Super Prototype that is also very dangerous to pilot, to the point that its use can produce fatal results, is reminiscent of the Wing Gundam Zero.
- In Episode 22, there's are two references during Suletta and Guel's fencing duel, one to Mobile Suit Gundam and One to Gundam Build Fighters,in that Like Amuro and Char, Suletta and Guel have a duel with fencing sabers, and Suletta performs the same technique Sei Iori did in his final battle against Meijin Kawaguchi, abeit she does it sucessfully. In addition, after defeating Guel, Suletta strikes the iconic "Last Shot" pose that both Amuro and Sei performed in their respective series.
- Episode 23 has Ericht using the Aerial and her GUND drones as a shield to protect her family from the beam fired by the Space Assembly League's Interplanetary Laser Transmission System, similar to how Banagher used the Unicorn as a shield to protect his home colony from the Federation's Colony Laser in Mobile Suit Gundam Unicorn. As well, Eri's seemingly last act is to look back at what she's protecting, similarly to Mu La Flaga's Heroic Sacrifice in Mobile Suit Gundam SEED.
- Episode 24 has Suletta and Prospera meeting the Permet Ghosts of Nadim, Elan Four, Nabo Cardo, and the rest of the Vanadis staff inside the Data Storm, a similar phenomenon to the Newtype Ghosts of Lalah-Su, Char, Amuro, and Rita, who appeared at various times during the UC era of Gundam. The way that Aerial, Quiet Zero, Calibarn, Schwarzette, and Pharact all sublimate after this final goodbye may remind some of the way things just dissolve in light when consumed by the Turn A's Moonlight Butterfly.
