On Rekka Namidare's first day of high school, a strange uniformed being named R claiming to be from the future appears before him and tells him that his indecisiveness has caused a war of epic proportions, and that he must work to prevent that future.
To elaborate: There are stories involving worlds being doomed, and a hero is needed to save the day. However, there are worlds where there is no such hero. Namidare males carry the responsibility to go to such worlds, save them, and be their hero. The trouble came when Rekka's efforts caused many heroines of those worlds to fall in love with him, and he was unable to choose any of them, resulting in them fighting over him, sparking the cosmic war in the future R came from. R's purpose is to make sure he actually chooses one of the heroines he saves.
Things get complicated when his childhood friend Satsuki Ootomo, who wrote a letter intending to confess to him, nearly gets kidnapped by a mysterious man, and in his haste to get away with Satsuki, he runs away with the wrong girl: an alien girl who had fled from an Arranged Marriage from another world and had just happened to be on Earth, and at the scene. After getting into her spaceship, he then gets summoned to yet another world which is in danger of being overrun by a demon king...
And that's just day one.
Ore ga Heroine o Tasukesugite Sekai ga Little Mokushiroku!?note , English title I Saved Too Many Girls and Caused the Apocalypse, is a Light Novel written by Namekojirushi with illustrations by Nao Watanuki (of Asura Cryin' fame). It was first published on June 1, 2011, and ran for sixteen volumes until October 27, 2019. A manga adaptation illustrated by Kouji Hasegawa was first released on April 27, 2012.
Tropes found in this series:
- Achilles' Heel: The Demon Overlord's first form in Harissa's story is invulnerable to all magic except holy magic. Subsequent forms are immune to all forms of magic... but Rekka has a laser gun.
- Action Girl: Most, if not all, of the heroines either are this or eventually become this.
- Arc Villain: The villains in each heroine's story are these in the overall scheme of things. Sometimes they overlap, such as Bahamut in volume 2.
- Akashic Records: Satsuki has access to this, which allows her to access information on any topic in the universe up to the current point in time.
- Alliterative Name: Harissa Hope.
- Anticlimax Boss: The Demon Overlord in Harissa's world, though in all fairness, he'd probably be better if his opponent didn't have a stupidly-powerful laser gun.
- Apologises a Lot: Harissa.
- Arranged Marriage: Iris is forced into one by her father. Rekka has to save her from it. To be fair to her father, he was literally blackmailed with the safety of his entire planet. And when Rekka gets involved, Earth comes under the gun as well.
- Battle Harem: Rekka's admirers are, or become, powerful fighters.
- The Beard: Iris tries to get Rekka to act as her lover to get out of an Arranged Marriage.
- Big Bads: In many of the worlds Rekka goes to there is some powerful villain causing trouble. Defeating them is a job for Rekka's family line.
- Breather Episode: Volume 6, which is a more street-level story with no "bad end" level threats, two new characters that may not offically count as heroines, and it opens with Rekka helping Lea get a part-time job.
- The Demon Overlord in Harrisa's story in Volume 1 turns out to be one of the three Demon Kings of the demon world, connected to the spirit world as shown in Volumes 7 and 8 (with the other two being Corona and the Big Bad of Lyun's story).
- The Call Knows Where You Live: Practically every heroine starts off showing herself before Rekka.
- Chick Magnet: Rekka attracts the heroines and even sub-heroines of whichever world he ends up in. One wonders what would happen if he ended up in places like Gamindustri or Gensokyo...
- Childhood Friend Romance: Satsuki is Rekka's childhood friend and was planning on confessing love for him at the start of the series.
- Chronic Hero Syndrome: All Namidare males are this due to their birthright. When a "story" has no hero, it goes to the Namidare as the last chance to not have a "bad end" for its heroine.
- Combat Pragmatist: Rekka will take any advantage he can get to resolve the stories he gets caught up in, such as using alien technology in a medieval fantasy world. The story itself doesn't care so long as it's resolved one way or another.
- Curbstomp Battle: Happens on a few occasions, particularly early on.
- When faced with the Demon King of Harissa's world, he is level 1 but armed with what amounts to a Wave-Motion Gun. The Demon King is able to regenerate, each time doubling his power and resistances, but still he's barely able to get three words in before his upper half is again vaporized. It is eventually demonstrated that he really did grow stronger with every new form, since his very last form wasn't vaporized but instead was merely barbecued all the way through.
- Dangerous 16th Birthday: Namidare males' responsibilities of saving stories begins on their sixteenth birthday.
- Extremely Short Timespan: In one day, Rekka manages to be the hero of Harissa's world by killing the Demon King, ended Satsuki's torment by defeating the most powerful magician, and managed to get the Satamonia kingdom to back down from Iris' marriage.
- Gonk: Iris' Arranged Marriage partner is hideous. No wonder she wanted to get out of it so badly. (Also, he has a bad attitude.)
- Good with Numbers: Harissa is able to calculate the coordinates of the Demon King's Lair, allowing Rekka to use his warp watch to help him bypass the barrier surrounding the lair. (And go back.)
- Irony: Apparently, Rekka died in the war where the heroines were fighting over him.
- Marry Them All: One of R's suggestions to prevent the war is to choose all of them. This could prevent the fighting, maybe.
- Nice Job Breaking It, Hero: Rekka knows that not following the plot line of each story could lead to complications. Of course, there's no saying that he can't bypass said complications the same way he created them either.
- An example is when when he nearly gets Harissa executed despite felling the Demon King because he didn't pull out the Hero's Sword from the rock before going to defeat it (thereby giving no proof of being an actual hero), and it couldn't be pulled out unless there was a Demon King to defeat. He uses Iris' warp watch to warp it out, as well as her Bag of Holding to transport the Demon King's head back as proof of his kill.
- Oblivious to Love: Rekka couldn't even figure out that Satsuki wanted to confess her love to him. R calls him out for it. In fact, this is implied to have contributed to his indecisiveness which led the heroines to end up fighting over him.
- Oh, Crap!: Rekka and Harissa panic on seeing the Demon King for the first time.
- One-Letter Name: R. And L. Not that L, though.
- Ordinary High-School Student: Rekka would have been ordinary if not for his lineage.
- Red String of Fate: Harissa gives Rekka a red string to allow him to return to her world anytime. She later finds out how to use them to create catalysts for "connection magic" to follow the karmic connections between an object a place or person, even across dimensions.
- The Reveal: R's report at the end of Volume 6 reveals R's story is accelerating the rate at which Rekka encounters new heroines. The epilogue of Volume 11 details this further: it's making it more likely that any girl Rekka interacts with outside his bloodline's calling becomes one of his heroines, such as Midori and President Momone.
- Science Versus Magic: Rekka fells the Demon King in Harissa's world with a laser gun.
- Screw the Rules, It's the Apocalypse!: Every world Rekka goes, he solves its problems via a means that totally does not follow its rules.
- Set Right What Once Went Wrong: R's aim is to prevent a bad future caused by Rekka refusing to choose from amongst his love interests, thus leading to a war. Though it has been backfiring so far; in the future R came from, only 80% of the heroines participated in the war, with the other 20% sitting out. Not only is the other 20% also likely to enter the war now, but the list of heroines has also increased from R's future.
- Spiritual Successor: The premise of "protagonist collides with girls from multiple worlds, Story-Breaker Team-Up ensues" resembles a Denser and Wackier, Victim of the Week version of INVADERS of the ROKUJYOUMA!?.
- Summon Magic: Harissa is a magician specializing in summoning creatures.
- Pastel, the summoner that called on the original hero, Corona.
- Talk to the Fist: Rekka doesn't let the Demon Overlord's second form finish its speech, and proceeds to blast all its forms into smithereens until it dies for real.
- Thanks for the Mammaries: Rekka gets quite a bit of the heroines' chests.
- There Is No Kill Like Overkill: The Demon King falls to Rekka's laser gun... which has the destructive force of a cannon. Harissa even feels sorry for the Demon King when it dies. It's basically a handheld Wave-Motion Gun!
- Unwanted Harem: One that would cause a cosmic war by fighting over you? Definitely unwanted. It's exaggerated to boot; the heroines he saved numbered in the hundreds.