Set 100 years into the future, mankind has been driven extinct following a war with the entities known as Metal Parasites, a mysterious army of machines who assimilate technology and go out of their way to ensure not a single human has been left alive. The only inhabitants left in the world are the Bioroids, powerful combat and utility androids in the form of beautiful women, and the Auto Guard System, a battalion of robotic soldiers, both unable to operate at full strength without the guidance of a human leader. However, upon the discovery of a surviving human who instinctively known how to battle the Metal Parasites, the Bioroids and AGS rally under him as their new Commander, bringing the war back to the monstrous machines as they work to wipe them out and plan the repopulation of Earth.
During gameplay, the player controls a squad of up to five mixed Bioroid or AGS units in a turn-based battle against waves of enemies, with each unit possessing a normal attack, a stronger attack and up to three passive abilities to aid in combat. As such, the player must strategize to use the best combination of units and make use of their synergies in order to defeat the enemies, who also work the same way.
Last Origin is perhaps most known for its extremely blatant Fanservice, to the point the uninitiated may confuse it for a H-Game at first glance. Another of its strengths is a firm philosophy of avoiding Temporary Online Content in regards to its units and skins; every one of them that has ever been added to the game is permanently available, no matter how much time has passed.
This game contains examples of:
- Achievement System: There is an extensive list of achievements, with each rewarding the player with items, including Tuna Cans.
- Action Girl: Every playable Bioroid is this by necessity, more than capable of fighting hordes of enemies.
- Adam and Eve Plot: The plan for what happens after the Metal Parasites are defeated is the Commander and the Bioroids will... repopulate the Earth. The Commander treats this with certain trepidation due to him being a Chivalrous Pervert at worst, but multiple Bioroids, like Royal Arsenal, are really looking forward to it.
- Amazon Brigade: The Bioroids are all girls of various shapes and ages, and are your main force against the Metal Parasites.
- Androids Are People, Too: The Commander's stance on the Bioroids, which is much unlike that of former humanity, who treated them extremely callously. The girls are deeply loyal to the Commander in return.
- And Your Reward Is Clothes: The vast majority of characters have multiple skins, which serve as the primary money sink of the game. Skins can be obtained either through free Mission Chests (extremely rarely), or by being bought with Tuna Cans, though a handful of characters possess skins that can be obtained as mission rewards, usually as part of their Side Stories.
- Anti-Frustration Features: Last Origin has a number of features that makes it very user-friendly in comparison to other gachas:
- Units and skins added to the game are available permanently. The game has a staunch anti-Temporary Online Content policy when it comes to this subject.
- Some of the game's events have been made permanent, serving as an excellent source of resources and units.
- While most events are temporary and work on rotation, progressing the main story unlocks the events' cutscenes in the game's Archives room when they are chronologically relevant, without needing to play through the levels.
- The Orca Pass is very easy to complete. While it lasts for a whole month, it can easily be completed in less than a week by just completing daily, weekly and monthly missions, many which overlap.
- While it isn't possible to create specific Bioroid units through the Workshop gacha, the game is extremely generous in handing them out, and almost every level drops a small selection of them for free. Many levels (particularly in events) even drop S and SS-tier units. This means the player can potentially max out most of the game's cast without ever having to use the gacha element.
- Apocalypse How: The Earth went through a Class 3a scenario by the time the game starts from a combination of massive world wars, the Metal Parasites and the Hypnos Disease finishing off what was left of humanity.
- Arc Villain: Some specific events and chapters have a specific threat taking over the spotlight:
- Aria of the Elven Town has Robert, Mr. Alfred's Evil Twin.
- Country within Muddy Memory and Chapter 8 have Lemonade Omega.
- Invitation from Paradise has Machina.
- Chapter 9 has Lemonade Gamma.
- Chapters 10 and 11 have Lemonade Delta.
- The Assimilator: One of the reasons the Metal Parasites are able to spread so much is their ability to do so with pieces of technology by implant larvae into them, including AGS units. A close inspection hints that most forms of Metal Parasite are assimilated AGS, as they have identical body frames.
- Attack Animal: Constantia has a Canine Companion named Bori who serves as her second attack skill. Dark Elven Forest Ranger, meanwhile, has a bald eagle that functions similarly.
- Beach Episode: The Legacy of Rioboros event. While Triaina and the Commander are focused on looking for treasure, most of the other Bioroids are taking the chance to relax at the beach and use their swimsuits, even if the Metal Parasites keep interrupting them.
- Because You Were Nice to Me: The primary reason why the Bioroids quickly endear themselves to the Commander. His genuine love and care for them, unlike any former humans who treated them as disposable tools, has earned him their Undying Loyalty.
- Benevolent A.I.: The AGS are one of the Commander's main allies and serve him with as much loyalty as the Bioroids do.
- Big Bad Ensemble:
- The Metal Parasites are the primary villains of the game. In particular, the leading Parasites known as the Connectors serve as the game's closest equivalent to a primary Big Bad, but they remain mostly unknown.
- Beginning with Zone 8, the Orca goes to war with the Secretary Lemonades - a group of powerful unique Bioroids aligned to the PECS Consortium who the Commander cannot control - who want to bring their masters back to life no matter the cost.
- Bowdlerise: The Japanese client has censored designs, covering the girls much more in comparison to the Korean version.
- Brain Uploading:
- Eva, the first Bioroid, was created this way, transplanting the mind of the human Eva Jones into an artificial body. This is not the case for subsequent Bioroids, however; they are all made from scratch, despite their human-like appearance.
- At the end of Chapter 6, the Commander's brain is uploaded into a male Bioroid body to save him from the Metal Parasite corruption that was consuming him.
- Brutal Bonus Level:
- Completing a zone unlocks a series of "Ex" levels which are substantially harder than the rest. These often drop rare items or higher tier units.
- The Challenge and Infinite War modes serve as this, putting the player against very hard encounters to earn special rewards.
- Cat Girl: Perrault and Poi are half-cat Bioroids.
- Chase Stops at Water: This is invoked by the Bioroids when fighting the Metal Parasites as, for unknown reasons, they refuse to go into the ocean. This also means having a submarine as their base leaves them safe from attacks unless they are near the shore. Later it is revealed the Parasites avoid the ocean because there are worse things there.
- Chick Magnet: The Commander quickly turns into this as more Bioroids flock to him due to his good treatment of them, especially in comparison to how other humans used to do it. Expect them to fawn over him often, especially during events.
- Chivalrous Pervert: The Commander can't help but indulge himself sometimes when the Bioroids keep throwing themselves at him, but he is always very respectful of them and is usually the one setting boundaries to keep things healthy.
- Christmas Episode: The St.Orca's Secret Operation event.
- Church Militant: The Kouhei Church was a religious faction made before the fall of humanity which created angel-themed Bioroids like Angel, Azazel and Saraqael, and over time became a pseudo-fanatic organization with equally fanatical Bioroid servants dedicated to the worship of the "Light". Its official description mentions these Bioroids had religious brainwashing engraved in their very genes, which was removed when they were reconstructed and made them more amiable.
- Com Mons: B-rank units like T-2 Brownie, Aqua and CT2199W Fallen serve as this, being rewarded in droves from most stages in the game.
- Cooking Duel: The "Supreme Dinner" event has one between Sowan, Perrault and Hachiko as they fight for the Commander's favor. Later, Doctor, Fortune and Gremlin ask to have their own hand at it, but due to them all being The Engineers, their food can only be consumed by Pupp Head, much to the Commander's disbelief.
- Cool Boat: The Orca, a huge submarine which serves as the Commander's headquarters. It comes in handy due to the Metal Parasites' aversion to water.
- Cosmetic Award: Some event levels feature fights with Superbosses that, when defeated, award the player's profile with an Orca Medal. They don't do anything other than let other players see how many of them you've earned.
- Crapsack World: The world was already in a pretty poor state before the Metal Parasites rolled in. Humanity descended into aggressive hedonism, mistreating Bioroids for their amusement in horrific ways despite their human appearance (including killing them for incredibly petty reasons), and corporations eventually begun taking over entire countries, leading to massive world wars motivated solely by greed. At their worst, they were basically Abusive Precursors by the time they died out.
- Crossover: October 2023 featured one with Sengoku Blade, adding Koyori and Kaen as playable characters. Canonically, they are Bioroids modeled after the game characters created for live-action adaptations.
- Cute Monster Girl: Many Bioroids are basically cute girls with some animal traits, such as Perrault and Poi (cats), Hachiko of Castling (dog) and Fenrir (wolf), and there are also more mature-bodied examples like Frigga (bear), Ajax (bison) and Alcyone (orca). The Companion Series's theme is combining this with Ninja Maid.
- Dark Action Girl: The antagonistic Secretary Lemonades (Lemonade Omega, Lemonade Gamma and Lemonade Delta).
- A Day in the Limelight:
- Side Stories feature a specific character's personal story, sometimes asking the player to have them at a certain level of affection to be unlocked.
- Events tend to center around a specific Bioroid who drives the plot. Supreme Dinner is centered around Sowan, Choco Queen in Wonderland centers around Aurora, etc.
- Dead All Along: When the Orca forces find Eva's location, she turned out to have been killed by Trickster, having been subject to Your Head A-Splode. It makes her later appearance be treated with much suspicion.
- Degraded Boss: Bosses found at the end of the main story's chapters appear again as fights in Daily Training and the Sanctum of Alteration, sometimes even having multiple of the same boss in the same wave.
- Demoted to Extra: Labiata is treated as The Leader among the Bioroid resistance during the first chapters of the story. However, after she joins the Orca, she practically disappears from the story outside of a scant few appearances.
- Eldritch Abomination: Chapter 7 reveals massive monstrosities known as Star Children live in the sea, resembling gigantic tentacled beasts. They are the reason the Metal Parasites avoid going into the ocean, and a massive battle between the Orca against one of them and a Parasite Connector serves as the climax of the chapter.
- Enemy Civil War: The Metal Parasites don't normally in-fight, but Chapter 2 features Predator, a powerful Parasite experimented on by humans that devous its own kind and reconstructs its body from them. It serves as the Boss Battle of the Chapter.
- Gameplay and Story Segregation: Unit acquisition doesn't match with story progression. It is perfectly possible for the player to, for example, obtain Vargr from an event or from the Workshop gacha while they are starting out, even though she doesn't canonically join the Orca until Chapter 10.
- Great Offscreen War: The First and Second Alliance Wars, which ocurred before the events of the game and contributed to its status as a Crapsack World. Corporations gained control over entire countries and laid waste to one another, which would make humanity much less prepared for the eventual emergence of the Metal Parasites.
- Going Commando: A lot of Bioroids wear no underwear, which can be easily told by how skimpy their outfits tend to be. Examples include Wraithy, Sekhmet of Death, Atalanta and Barbariana.
- This is outright considered a religious matter for the Kouhei Church. None of its affiliated Bioroids wear any panties, treating doing so as more depraved than going commando.
- Failed a Spot Check: The whole crew of the Orca missed the fact that the Commander was undergoing Metal Parasite corruption until Labiata met him in person. This is explained in-game as Labiata being the only Bioroid in the Orca to be old enough to have seen a living human; the others had no clue what they were supposed to look like, only detecting the Commander as human from his brainwaves, and were none the wiser as a result. This would make sense... except that Indomitable Marie, another Bioroid who predates humanity's extinction, had already joined the Orca and spoke to the Commander in person multiple times by that point.
- Fantastic Racism:
- Humans had this towards Bioroids, treating them as disposable tools at best. Any person showing sympathy towards them would be singled out as strange for doing so.
- The AGS are said to not see Bioroids as equals, seeing them as ones to protect rather than fellow soldiers or allies. This is mostly an Informed Attribute, as they can be used together in squads without any penalties.
- Fetch Quest: While the gameplay doesn't change in any way, some side missions' context are functionally this, such as Fortune asking the Commander for spare parts or Parasite remains for study, or Griffon and LRL convincing the Commander to look for Tuna Cans for them to eat.
- Halloween Episode: The Halloween Park Panic! event.
- Foreshadowing: Early in Chapter 3, Aeda comments on how only two Tricksters have ever been seen. At the end of the Chapter, after the 3-8 boss fight, it turns out both of these Tricksters were present all along, with the Orca killing one while the other - their actual target - took the chance to flee.
- Horde of Alien Locusts: While the alien part is ambiguous, the Metal Parasites otherwise fit the trope to a T.
- Horrifying the Horror: The Metal Parasites avoid the ocean at all costs due to the Star Children being there.
- Humans Are Bastards: The game really pulls no punches at portraying humanity as positively vile before it went extinct. Almost every human character seen in a flashback is a Jerkass who employs We Have Reserves and Just a Machine towards Bioroids, with their treatment of them sometimes just being petty and callous for no good reason. The Commander is appalled whenever he learns of the atrocities commited by humanity.
- Inside a Computer System:
- Most of Chapter 6 takes place inside virtual reality, with the Commander using a VR headset in order to look for important information.
- The Country within Muddy Memory event likewise takes place in virtual reality, taking the form of a game in which the Commander takes direct control of one of the main characters.
- It Can Think: The Bioroids mostly believe the Metal Parasites to be mindless machines, but the Connectors are able to coordinate them. Following the final battle with Trickster, the Orca learns that they can speak as well, but curiously, only the Commander is capable of understanding them.
- Just a Machine: Flashbacks show that humans overwhelmingly treated Bioroids as this, treating them as disposable soldiers, playthings or worse, with any who showed sympathy for them being admonished for doing so. The fact the Commander firmly averts this is one of the reason the units have an Undying Loyalty to him.
- Kid Hero: The child Bioroids are equally capable in a fight in comparison to the adult ones. Examples include LRL, CoCo, Dutch Girl and Ellie Quickhand.
- Last of His Kind: The Commander is the last living human (and the last living male, outside of any AGS units who may identify as male), thus making him the Last Origin.
- Male Gaze: Pretty much the main selling point of the game. Virtually every girl is a Ms. Fanservice with Stripperiffic skins.
- Mechanical Lifeforms: The Metal Parasites are living machines, repeatedly described as being Silicon-Based Life, who proliferate by implanting their larvae on human technology and converting it into more of themselves.
- Microtransactions: Naturally, as a gacha game. Real money can be used to purchase Tuna Cans, which in turn can be exchanged for items and resources.
- Ms. Fanservice: Every Bioroid with an adult body is this. Some are more blatant than others. The less blatant ones often have skins that up the ante.
- Naughty Nuns: Alice, T-75 War Wolf, Charlotte and Cardinal Armand all have skins that make them look like naughty nuns. Veronica looks like one by default.
- Ninja Maid: Every Bioroid of the Project Battle Maid faction is this (including Labiata, Constantia, Vanilla, KeumRan, etc). The Companion Series faction (Perrault, Fenrir, Hachiko of Castling, etc) combines this with Cute Monster Girl.
- Number Two: Constantia S2 is this to the Commander, not only being his head maid but also being his closest confidant. She remains by his side even after the military generals among the Bioroids like Royal Arsenal and Leona join them in the Orca.
- One-Gender Race: Bioroids are exclusively female. The backstory shows this used to be subverted; male Bioroid models called T-1 Goblins used to exist, but were decommissioned due to undergoing dangerous bursts of Unstoppable Rage if their masters were wronged, to the point they massacred other humans, including children.
- One Nation Under Copyright: Following the invention of Bioroids, this ended up happening to Earth, with business companies responsible for their manufacting eventually becoming powerful enough to exert control over entire countries.
- Our Angels Are Different: Angel, Azazel, Ramiel and Saraqael are Bioroids based on angels, created by the Kouhei Church to spread their influence. Being Bioroids, they aren't actually supernatural creatures, though their demeanor and abilities invoke religious angels through and through. Angel is specifically described as a Cherub, while Azazel is a Seraph.
- Our Elves Are Different: Multiple Bioroids are based on pointy eared elves. While half of them (Elven Forest Maker, Dark Elven Forest Ranger and Cerestia of Life) are based around a connection to nature, Sekhmet of Death and Hathor are instead themed around Egyptian gods.
- Our Vampires Are Different: Cyclops Princess and Draculina are both designed to invoke vampires, though the latter is much more pronounced than the former and looks like a typical vampire in comparison, being named after Dracula and commanding little robots shaped like bats during her attacks. With that said, she doesn't drink blood, only tomato juice.
- Playboy Bunny: The skin store has an entire "Bunny Girl" category for characters with such skins. T-20S Gnome, Rhea, Aurora and Titania Frost are among the girls who have them.
- Premium Currency: Tuna Cans serve as this in this game.
- Really 700 Years Old: Certain units encountered during the story, like Labiata, RF87 Roc, Circe and Cerestia of Life were produced before the extinction of humanity, making them over 100 years old by the time the Commander meets them.
- Relationship Values: Bioroid units have an Affection mechanic, with the value ranging from 0 to an initial cap of 100, which can be increased up to 200 by gifting them bouquets. Affection can be gained by using them in battle, giving them gifts and not letting them be defeated during a fight. Reaching 200 affection grants stat bonuses to the character, and reaching 100 allows you to use a Pledge Ring to become Happily Married to the Bioroid, permanently locking her at max affection. The player can marry multiple girls without any drawbacks, basically turning the roster into your very own Battle Harem.
- Remember the New Guy?: While many characters have a proper introduction during the main story, some Bioroids like Tomo, Daphne and the Doom Bringers simply show up in cutscenes acting like they were already there, making it difficult to tell when or how they joined the Orca since Gameplay and Story Segregation is played straight with unit acquisition.
- Restraining Bolt: Bioroids are unable to fight at full capacity or destroy things without an order from a human leader, only being able to defend against the Metal Parasites rather than go on the offensive. The story begins with the Commander having to give a Destruction Order that finally gives them a proper fighting chance against the enemies.
- Rewards Pass: The game has one in the form of the Orca Pass, which cycles monthly and comes with a free and a paid half, each with its own set of rewards and with the paid part naturally having the fancier items. The Pass is the most rewarding way of acquiring Tuna Cans outside of flat out purchasing them for money.
- Ridiculously Human Robots: The average Bioroid is completely indistinguishable from a human woman from a glance. Aside from artificial skeletons and using Origin Dust for their brains, they are functionally human on the inside as well, including having fully functional reproductive systems able to conceive human offspring.
- Robot Soldier: The AGS are this, being completely mechanical in comparison to the Bioroids.
- Sexy Discretion Shot: Using a Secret Room Key in the base while an adult Bioroid is in the Secret Room leads to a Fade to Black as the Commander is all but stated to have sex with her.
- Single Specimen Species: Single Specimen Model, in this case. Unlike all other Bioroids who were created to be mass produced, Labiata, Invincible Dragon and the Lemonades are one-of-a-kind individuals. This is relevant to gameplay; it is impossible to produce these units in the Workshop, meaning the only way to obtain them is by progressing through the main campaign, and the only way to increase their Core Links efficiently is by using rare Special Alternate Cores.
- Single-Target Sexuality: Most Bioroids have this towards the Commander. Kind of a Justified Trope given they don't exactly have any other options.
- Slipping a Mickey: Sowan drugs the Commander's meals when she first starts serving in the Orca, which puts him in some sort of half-conscious trance that makes him pliable to her advances before the other maids get her to stop. Supplementary material indicates she got the idea from a previous master before humanity's extinction who was implied to drug and Date Rape his girlfriends (clearly intending on doing it to him in response), though Sowan doesn't go that far with the Commander. At the end of the "Supreme Dinner" event, when the Commander gets too picky with food, the maids all join forces and drug him again to get him to cut it out.
- Succubi and Incubi: Alice, MH-4 Thetis, Maria of Redemption, AO-2 Raven and Eternity all have succubus-themed skins.
- Superboss:
- Some events feature extra hard versions of boss fights which reward Orca Medals when completed.
- The Infinite War mode revolves around fighting these, who are uniquely powerful Metal Parasites who act as the only source of Altite, which can be exchanged for powerful rewards.
- Super-Deformed: Characters are depicted as chibis during combat or in the base screen.
- There Is Another:
- Chapter 3 ends in a battle against Trickster, one of the Metal Parasite Connectors. After killing it, the Commander quickly connects the dots from his demeanor and realizes there is actually a second Trickster, who was the one they were actually chasing.
- After destroying the Under Watcher in Chapter 5, an Ex-level is unlocked featuring a fight with an even stronger one, created as a spare in case the original was defeated.
- Tsundere: Griffon, May of Doom, Vanilla and Draculina all share this archetype.
- Undying Loyalty: Bioroids appear to be programmed to have this towards humans by default, being largely incapable of disobeying orders even if they want to. It reaches the point that they cannot fight off the Metal Parasites at full capacity without having a human to order them.
- The Bioroids have this towards the Commander, following his orders to the letter and ensuring his safety, due to his good treatment of them. When Labiata threatens to cut him down due to his Parasite infection, Constantia responds by holding her (who at this point is essentially The Leader of the Bioroid resistance and their most esteemed general) at gunpoint.
- The Secretary Lemonades Omega, Gamma and Delta have this towards the CEOs of PECS. Tellingly, they are the only Bioroids who are able to reject orders from the Commander.
- The Virus: The Hypnos Disease, a deadly pathogen which served as the final nail on humanity's coffin, seemingly appearing out of nowhere amidst the war with the Metal Parasites. The infection affected the brains of humans, who invariably fell into a nightmare-filled coma that led to death by starvation or dehydration. The Bioroids are immune to it, however, due to their Origin Dust-based brain structure.
- Was Once a Man: Eva, the first Bioroid ever created, was originally a human by the name of Eva Jones who offered herself to be turned into a Bioroid.
- We Can Rebuild Him: This is done to the Commander at the end of Chapter 6, where advanced technology is used to reconstruct his body, effectively turning him into a male Bioroid. It saves him from Metal Parasite infection and gives him immunity to the Hypnos Disease.
- We Have Reserves: Bioroids were designed to be mass produced, and humanity made ample use of this before it went extinct. It wasn't limited to military uses; Prester Johanna's Side Story shows an example of a director having an acting Bioroid being genuinely killed for the sake of authenticity, and it is treated as something completely normal, with said director simply asking for an identical model to replace the dead one. The Commander is firmly against this sort of treatment of his troops, however.
- What Measure Is a Non-Human?: Humanity's treatment towards the Bioroids makes up a significant portion of its backstory, and how the Commander is able to do things difference cements him as a true leader in their eyes.
- Winged Humanoid: All the Bioroids of the Fairy Series have fairy wings which lets them either fly or levitate. Angel, Azazel, Saraqael and Ramiel meanwhile have feathered angel wings, though Ramiel cannot fly with hers.
- World of Buxom: Well over half of the game's playable roster is made up of very well endowed ladies, to the point this is arguably the reason most people know this game at all.
- Yandere: Scissors Lise's character is based on this archetype. Black Lilith and Sowan also have some shades of it, but those two are far more composed in their demeanor and relent on it, while the former doesn't. Amusingly, Scissors Lise and Black Lilith end up butting heads because of it and can't stand each other as a result.
- You Are in Command Now: The story begins with the Commander being given his title, even though he had just woken up in the middle of nowhere with with no memory of his past or how he got there.
