The Remnant / Anime Manga

• After War Gundam X has the New Earth Federation start to make trouble about a third of the way through as they campaign to "unify" (read: conquer) the emerging new nations. They're surprisingly effective and achieve their goal quickly. Meanwhile, around the Moon, the Space Revolutionary Army is doing the same thing. Both sides are enemies and both lost because of the mass Colony Drop that wiped out Earth and Spacenoids alike... and both of them still want to kill each other.
• In Attack on Titan, the Walled City is pretty much all that's left of human civilization (at least as far as it's known) after the Titans ate everyone else.
  • The big reveal in the basement is that the Walled City is not the last bastion of humanity; every other human civilization is doing just fine and is (at least mostly) free of Titans. However, the city is the last "free" remnant of what was once the Eldian Empire; in the rest of the world, the Eldians are second-class citizens who live in segregated ghettos, due to their connection to the Titans.
  • Half of the survey corps are turned into this following Eren's insurrection, with the Titans destroying the countries of the world and enslaving what's left of Paradis.
• The last prime minister of Japan in Code Geass is treated somewhat like this trope... But he never got to go through with it because his son Suzaku killed him. It's heavily implied that Britannia would have eradicated Japan utterly if he had.
  • The Japanese Liberation Front was the remnant of the old Japanese army until the Black Knights absorbed them.
  • What is left of the old Japanese military is killed off by Britannia and the Black Knights, as they crossed the Moral Event Horizon by throwing hostages off a building in the name of the 'glory of Japan'.
• The character Grenadier in the Leiji Matsumoto series Cosmo Warrior Zero (an Alternate Universe spinoff of Captain Harlock) starts off as one of these, despite being a mercenary soldier hired by La Résistance; blame Honor Before Reason, a group of refugee children to protect, and a very open-ended contract.
• Dragon Ball:
  • In Dragon Ball Z, Dr. Gero and his Androids are technically this — the Red Ribbon Army is long defunct as an organization, but Gero, one of its founding members, tries to continue the cause, though with a heavy focus on killing Goku, partly because Gero wants revenge because Goku is responsible for the Army's defeat in the original Dragon Ball, though it's also out of practicality, since Goku would likely interfere anyway. In both Trunks' timeline and in the regular timeline, his plans are a bit too effective in so many ways, but he never lives to see it happen. It's not drawn attention to, but the Red Ribbon Army iconography is notable on all of Gero's androids except Cell. The Red Ribbon Army as an organization also are the main antagonists of Dragon Ball Fighter Z, even if it's basically just Android 21 at that point. They fully make a comeback in Dragon Ball Super: Super Hero under the leadership of Overlord Jr. Magenta, who's revealed to have been bankrolling Gero's experiments this entire time and recruits his grandson to continue his work.
  • In Dragon Ball Z: Resurrection 'F', and the corresponding arc of Dragon Ball Super, Frieza's Empire has been reduced to a shell of its former self after King Cold and Frieza were killed along with most of their high ranking minions. The remnant of his empire is losing planets at a rapid rate to the point that what little is left decides to resurrect him as a last resort to restore the fear of them they need to keep the Empire afloat. Unfortunately for them, Frieza is more focused on revenge on the ones who defeated him than doing that. This results in Frieza being killed again and the rest of his army being killed as well.
• The Kiheitai in Gintama is a revolutionary army that seeks to violently drive the Amanto aliens out of Japan, even if it means that Japan will be destroyed in the process. In fact, the complete and total destruction of Japanese society under Amanto influence seems to be the desired goal of this group's leader, Takasugi, who has shown both a willingness and a creepy enthusiasm to do the destroying himself. Then again, Takasugi is also a Nietzsche Wannabe and seems solely interested in destruction and avenging his teacher's death.
• The Millennium Group from Hellsing is a single battalion of Nazi soldiers who have voluntarily undergone artificial vampirification in their mission to give World War II another go. They're a variation on the usual type, since they're not fighting for Nazism, but because they really like war. Especially the Major, their mad leader. There used to be some actual Nazi die-hards in charge of the organization, but the Major had them all killed.
• Diana in Jewelpet (2009) turns out to be this after her big brother Dian's backstory is revealed (he was a Malcolm Xerox-flavored rebel). She managed to escape Dian's fate and many years later saw an opportunity to unseal him using the power of the Jewelpets who got lost on Earth; this is what the heroes try to stop during the first half of the show.
• Hegemon Heidi Einhard Stratos Ingvalt of Magical Girl Lyrical Nanoha ViVid is a subversion. Nove assumes her reasons for wanting to fight Vivio and Ixpellia is because to her the wars of Ancient Belka never ended, but Einhard denies this saying she only wants to prove the superiority of her Kaiser Arts. Once she actually meets Vivio, she quickly becomes The Rival and doesn't hold any grudges against her (quite the opposite actually).
• The Principality of Zeon, from Mobile Suit Gundam, has scads of these; there are at least five separate groups that appear in the animation, and it's implied that there are more. The single largest one fled to the asteroid base Axis and became the first Neo Zeon movement in Zeta Gundam; the others include the Delaz Fleet, Cima's marines, and the Kimbareid force (all in Gundam 0083), as well as Rommel's force (in Gundam ZZ).
  • The furthest extension of this appears in Gundam F90, centering on Zeon remnants who've been hiding on Mars for nearly fifty years before making their move.
  • The second Neo-Zeon movement in Mobile Suit Gundam: Char's Counterattack isn't really composed of remnants from the Principality of Zeon but is rather composed of ex-AEUG and other spacenoids who have taken a radical bent, though it is led by Char Aznable, a Zeon war hero and prince of its usurped royal family. It gets its own remnant in Mobile Suit Gundam Unicorn, in the form of the Sleeves, led by Char Clone Full Frontal.
  • In addition to the Sleeves, Gundam Unicorn also has the Zeon Remnant, both of who manage to eke out livings in various isolated places on Earth, and who band together to continue the war against the Federation in an ambitious attack on Torrington Base while also living out in space on the asteroid Palau. They're not exclusively military either, as many of their Earth camps include numerous civilians.
• Mobile Suit Zeta Gundam: After the defeat of the Titans at the climax of the show, their remnants occasionally pop up in Gundam canon, though not nearly as often as Zeon. In-Universe it's established that many Titans either rejoined the Federation or defected to Zeon. Though Zeta's sequel Mobile Suit Gundam ZZ notes that several Titans still hold political seats in government, the faction itself is too beaten down to be of any real threat to the protagonists and they only return in expanded material. Mobile Suit Moon Gundam featured a remnant fielding the Psycho Gundam Mk. IV while Gundam Sentinel featured a group called The New Desides and their attempts to rebel and fight the Federation.
• My Hero Academia: The Shie Hassaikai is one of the last remaining Yakuza organizations in the setting. As explained, after the rise of All Might and the era of heroes, the yakuza were labelled as villains and were thoroughly eradicated to the point that most of society has completely forgotten about them: when the Shie Hassaikai led by Kai Chisaki AKA Overhaul faced the League of Villains, not only had Magne never even seen one before Overhaul, but Toga didn't even know what a Yakuza was and Mr. Compress derided Overhaul as "an endangered species left over from old times". Overhaul eventually revealed the objective of the organization is to revert society to pre-quirk times and to bring the Yakuza back to its former glory for the man who brought him into the group.
• Fate Averruncus of Negima! Magister Negi Magi. Manga only though, the anime renders this impossible for plot altering reasons. Fate was second in command of a group called Cosmo Entelecheia, a group that was trying to bring about the end of the world A.K.A. "The Ritual To Return The World To Nothing". The group was lead by someone who was only known as "The Life Maker" and "The Mage of the Beginning". They fueled a war in order to accomplish this. It was the war and the defeat of The Mage Of The Beginning that made Nagi Springfield (protagonist's father) a legend. After that he was known as "The Invincible Thousand Master" or just The Thousand Master for short. Fate hasn't given up. Or he might be the newest version of the second in command of Cosmo Entelecheia.
• Many antagonists of Pumpkin Scissors are this type.
• Rebuild World:
  • The Neglectful Precursors known as the Old World left behind Artificial Intelligence and several sorts of monsters which serve as their security systems, usually trying to fulfil some half-defunct purpose (like making factory items and then storing them away because they're "out of season" despite being precious Lost Technology to humans). The A.I.s each have their own objective, Tsubaki trying to protect her sector of an otherwise ruined city, Olivia being a Robot Maid gun for hire under her company, and Alice trying to rebuild the Lion Steel MegaCorp. And Alpha's objectives are mysterious.
  • A new Renegade Splinter Faction forms over the course of a story that's the remnant of Katsuya's Cult of Personality and Battle Harem, led by Airi under Alpha/Alias' influence, and seeking revenge on Akira, Airi having taken the rest out of Drankam and vanished.
  • The remains of the Ezont and Hauritas N.G.O. Superpower gangs that Akira took down in a Roaring Rampage of Rescue, join in on the enemy's side in The Siege arc, to try and claw back their previous domination over the slums from Sheryl.
• In SOS! Tokyo Metro Explorers: The Next, taking place roughly in our time, an old man living under Tokyo still believes WWII continues, and is obsessed about the mission given to him. Other underground dwellers consider him dangerously crazy, but he is quite likeable.
• Viral in Tengen Toppa Gurren Lagann fits this role early on after the Time Skip, although subverted in that while being classified as a terrorist and gets told several times that his fight is pointless, he still insists that he does it for a noble goal. It is later revealed that he did, in fact, fight for a good cause; he was fighting not out of revenge, but on behalf of humans who actually wanted to live underground in defiance of Rossiu's commands to come up to the surface. He does grow out of this role when he joins up with the heroes, and eventually ends up as the supreme commander of the galactic federation fleet.
• Trapped in a Dating Sim: The World of Otome Games is Tough for Mobs: Most life traces back to one of two sides to a genocidal Great Offscreen War between Transhuman New Mankind and Old Mankind, ancestry of the former being how humans can use magic. Monsters and Artificial Intelligence of a robotic nature, are from Old Mankind, while Organic Technology ones are from the New Mankind Abusive Precursors.