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Stemothers sin 1 head small11

Gibo is an H-game and an anime with the title Stepmother's Sin, that has some dark themes, and puts the player in the shoes of a Villain Protagonist.

The game and the anime are kicked off by a flashback where your protagonist (Yusuke Yagami) remembers a heartbreaking memory of his mother's adultery. During his childhood, Yusuke witnessed his mother having extremely passionate sex with her lover in their home during his father's absence, and to his heartbreaking despair, the lady is immensely enjoying the sex and shown to have absolutely no remorse about cheating on her husband.  Traumatized forever since then, Yusuke assumes all mothers are secretly cheating sluts who deserve whatever suffering they might get.

That said, his father remarries to a woman named Misako, and one actually gets to see what would happen if Yusuke fufilled his dark desires in this regard. Throw a naive new stepsister (Shiina) into the mix, and this is a really dark game.

Tropes used in Gibo include:


  • Asshole Victim: Yusuke's default view of Misako, albeit minus any potential sympathy though the "good" endings can have him ease off on his more obvious Jerkass tendencies.
    • Shiina also gets hit with this, albeit the lion's share of his hatred is directed at Misako.
  • Beauty Mark: As seen above, Misako has one.
  • Big Damn Villains: Yusuke can technically get a moment or two of this in some scenarios, though it's really hard to cheer for him.
  • Downer Ending: Technically all of them are this. Either you die, or Yusuke, who is a total Jerkass at best, gets away with sexual torture and extortion scot free, and gets to keep getting laid with one [or more] of the other protagonists to boot.
  • Expy: Yusuke Yagami looks like Light Yagami somewhat. It doesn't help he has a cynical, nihilistic frame of mind, and that he has already decided the targets of his hatred [cheating mothers] will be punished by any means necessary.
  • Freudian Excuse: A somewhat petty yet plausible one for your protagonist.
  • Hanging Judge: Yusuke already declared Misako guilty of being a cheating slut before that was even proven, and was already planning to punish her.
  • Hot Mom: Misako... though that is not a fact to her advantage. Yusuke's actual mother, seen in flashback during her adultery, was also a very beautiful mother with an extremely attractive body
  • H-Game POV Character: Yusuke is a Type VI A.
  • Kissing Cousins: More like have had sex repeatedly and shamelessly cousins.
  • Incest Is Relative: Your protagonist's occasional lover is his cousin (Mio), who is basically his female counterpart. In fact, EVERY possible coupling in the game falls under this.
    • If you wind up with your cousin, it also overlaps with Unholy Matrimony.
        • Ironically, in the best of the Multiple Endings (which is actually one hell of a wallbanger as it is incompatible with the rest of the story, considering the ages of the characters, but what the hell) you learn that Misako is in fact, really Yusuke's mother (Parental Incest), the very same woman who caused his Start of Darkness (pay careful attention to her appearance in the flashback), and that Shiina is in fact, really his half-sister (Brother-Sister Incest) who was conceived from that adulterous union she had. In this ending, it is also revealed that Misako has become pregnant with Yusuke's baby, making Yusuke both brother and father to Misako's 3rd child. Cue the obvious Fridge Horror, as well as Fridge Brilliance, because Misako had revealed earlier in the game that she had originally married young in a loveless arranged marriage which later ended in divorce, and her current re-marriage to Yusuke's father is once again just the same, merely the result only of a debt she owed someone, as well as the need to provide for Shiina. If you get this ending and connect it with her earlier revelation, it implies that her said first marriage was the one involving Yusuke's father — thus possibly explaining her infidelity — and it can be used to explain why Yusuke's father even bothered to marry her again: as a gift to Yusuke, so his son can be finally reunited with his mother at last, since it appears that Yusuke's father is not really interested in cohabiting again with Misako anymore, as it is mentioned that he moved to and now lives at a new separate address from Yusuke, who remains at their original home, where Misako and Shiina now reside too. The only question is, why didn't Yusuke recognize her in the first place, considering that she looks virtually identical in flashback? Of course, he was just a young boy then but not that young so as to forget his own mother's face, unless he consciously blocked it from his memory.
  • Love Redeems: In the literally-named "Redemption" ending, Misako and Shiina run away, but Misako returns and reveals everything to Yusuke. They manage to forgive each other, and then live together as a couple (despite now knowing they actually are parent-and-child), as they are to become parents together of their own child.
  • Manipulative Bastard: Yusuke. Mio has her moments too.
  • Magnificent Bastard: In some endings, you just have to admire how well things have worked out for him, even if he is the world's most loathsome prick.
  • NaïveNewcomer - Misako and Shiina.
  • Pet the Dog: Despite being a total bastard, you are given the option to have your Villain Protagonist do something somewhat noble on occasion.
  • Sick and Wrong: Yusuke is willing to do some very depraved things in his quest to make "cheating whore wives" suffer.
  • Son of a Whore: Why Yusuke hates his mother.
  • Stepford Smiler: The protagonist, played totally straight.
  • Too Dumb to Live: Yusuke sees the targets of his rage as this, though in some of the bad endings this comes back to lethally bite him on the ass.
  • Villainous Incest: All possible sex partners for Yusuke are related to him. Taken even further with his relationship with Mio, who's not exactly a nice person either.
  • Villain Protagonist: It's a game mostly about the protagonist raping people.
  • What the Hell, Player?: Some choices, such as being too perverted or outright raping Shiina when Misako has begged you to spare her, prompt a bad ending in which Misako leaves the household and leaves a letter berating Yusuke (and, by proxy, the player) for his actions. Some of them are mildly humorous ("You pervert;") but most are outright WTHP?s.


  • Abusive Parents: In the hentai anime, though unintentionally and unknowingly, Yusuke's mother had deeply traumatized her son forever emotionally by having sex with another man while her son is at home which he had witnessed multiple times in the anime the first being accidental as Yusuke was out and had just arrived at home and again when he continued to peek on her sex sessions while he is at home. Ultimately, she no longer cared about Yusuke as not only would she risked being caught during her sex sessions, when she divorced her husband, she was perfectly content to give up custody of her son to his father to start a new life with her lover without any guilt or remorse.
  • Adaptation Expansion: The OVA also expanded to show and extended the scene of Yusuke's Mother commiting her first adultery and explained her reasons for doing so as well as how Yusuke discovered his mother's adultery. While the Visual Novel only showed Yusuke's Mother having sex in standing reverse cowgirl position with her lover, the OVA showed Yusuke's Mother giving her lover a fellatio, as well as her lover licking and fondling Yusuke's Mother breasts and giving her a cunnilingus. Yusuke's Mother was also shown having sex with her lover in the Missionary positon, Reverse Cow Girl position, Standing Sex Position and Doggy Style Position.
  • Beautiful All Along: Beneath the plain and modest clothings Yusuke's mother wore as a housewife all the time, is a immensely sexy, attractive and curvaceous womanly physique full of wonderous adult charm even after she had given birth which her lover found it almost impossible to believed.
  • Be Careful What You Wish For: Yusuku uses manipulation and blackmail to turn his stepmother Misako into a willing nympho as a way to get revenge on his neglectful birth mother, but eventually he starts to regret how badly he's treated his new family and asks for forgiveness. Misako rejects his feelings, telling him that he wanted a whore instead of a mother all along, and demands that he has illicit sex with her non-stop.
  • Buxom Is Better: More prominently shown in the hentai anime, Yusuke's mother is shown to be extremely voluptous with enormous breasts which are not only large but their shape are extremely beautiful and attractive. Her breasts are so huge they are larger than her lover's hands and they would energetically bounced when they are in doggy style sex position.
  • Break the Cutie: After Yusuke manipulates his stepmother into a sexual relationship, he turns his attention to his innocent stepsister Shiina, raping her in front of her mother to humiliate both of them. Eventually, Shiina is mentally broken and catatonic from all the abuse, and has become a sex toy for Yusuke's "friends".
  • Cicadian Rhythm: In the OVA from the start, Japanese Cicadas were heard nosily chirping during the background and also when Yusuke first discovered his mother's adultery. Japanese Cicadas chirps in order to attract a mate to themselves for mating with each other, which parallels and foretells the moment Yusuke's Mother started having extramarital sex with her lover during summer.
  • Gainax Ending: Near the end of the hentai anime, we see Yusuke being brought home by the police only to see Misako and the three guys she previously had sex with. Suddenly, a gun goes off, leaving questions as to whether Yusuke shot his mother or himself.
  • Good Parents: As far as Yuusuke could remember before witnessing her adultery, his mother was very loving and caring towards him, before she began to neglect him after she started cheating on her husband to the point, she is willing to risk getting caught admist her adulterous sex by her son while he is at home.
  • Happily Divorced: In the anime, according to Mio, Yusuke's mother remained happy and well even after divorcing her husband and abandoning her son to start a new sexual life with her lover.
  • Hey, It's That Voice!: You'll never hear Yami "Yugi" Moto the same way again after hearing Dan Green as Yusuke.
  • Hot Mom: As seen in flashback during her passionate adulterous sex sessions in the hentai anime, Yusuke's mother was also very beautiful and attractive with a vigorously sexy and voluptous figure with soft and elastic buxom breasts and also a pretty and nice pussy which remains completely untarnished despite having conceived and birthed a son several years ago. Enough that her lover who already had vast amount of sexual experience with women first hand consensually desired to have sex with her as they continued to engaged in adultery, mutually enjoying the infinite pleasure that was born from their sexual union for a long time to come.
  • Ignorance Is Bliss: Yusuke's mother had never realised that her son has already witnessed her adultery with his own eyes and who from time to time, continued to peek on her adulterous sex session with her lover.
  • Love Makes You Evil: Yusuke's mother new found love for her lover and the tremendous pleasure that was born from their adultery not only corrupted her from a loving mother into a hopeless and shameless nymphomaniac but also a neglective mother to her son Yusuke as she was perfectly to abandoned him without a shred of care, guilt or remorse.
  • Lovable Sex Maniac: Even after betraying her husband and abandoning her son, Yusuke still dearly loved his mother subconciously which in the hentai anime Mio correctly noted despite all the claims of hating his mother, Yusuke still craved for her love and almost came to find closure by believeing he was wrong to hate his own mother.
  • Official Couple: According to the dialogue in the hentai anime, Yusuke's mother's adultery was started with pure and benevolent intentions. Due to being completely neglected by her inattentive husband who is always away on business, Yusuke's mother sought the help of another man, a bespectacled middle aged gentleman with a vigorous and powerful libido who is extremely skilled and experienced in coitus and giving women sexual pleasure who is somehow familiar with her husband and son to train her in sexual techniques such as giving blowjobs so that she can regain Yusuke's father's attention and discourage her husband from cheating on her. However, overtime admist the throes of passion she developed tremendous romantic love for her sex teacher and most of all for the tremendous sexual pleasure she could enjoy with him. The adulterers officially became lovers as Yusuke's mother no longer cared about gaining her husband's attention as she spent all the time she could engaging in adulterous lovemaking with her lover during her husband near-endlessly long working hours in the Yagami's residence even when her son Yusuke was at home which she once simply dismissed with the convenient excuse that he is outside their house busy collecting insects and won't discover her adultery. Their adulterous and sexual bond became so unbreakable, she was perfectly content to divorce her husband and abandon her son to start a new life with her lover.
  • Romance: Yusuke's mother found a new unbreakable love in her sexual partner due to all the countless time he had spent passionately making love to her and the estactic pleasure that was born from their consensual coitus which is more than enough to satisfy the loneliness she felt from her husband's neglect. And she had no qualms being divorced and also abandoning her son due to her bond her lover.
  • Sex Is Good: Yusuke's mother became a lustful nymphomaniac who immensely enjoyed her adulterous sex with her lover and has absolutely no remorse or guilt in cheating on her husband.
  • Skinship Grope: In the hentai anime, Yusuke's mother had her rich, enormous and beautiful breasts groped by her lover which he deeply enjoyed and relished as he licked her nipples and again while he was thrusting his penis into her pussy till he ejaculated inside her womb.
  • Son of a Whore: Yusuke Yagami, he became the son of a whore right when his mother started committing adultery in his primary school years. 
  • Teacher-Student Romance: Yusuke's mother and her lover relationship was originally one of a sex teacher teaching a housewife how to have good sex so her husband wouldn't leave her. 
  • Ugly Guy, Hot Wife: In the hentai anime, Yusuke's mother is very beautiful and attractive even without any makeup and accessories while her lover is a plain looking man with a short mustache and a pair of spectacles who aside from a powerful libido looked like a middle aged geek in appearance.
  • Villainous Breakdown: The realization of the damage he inflicted to his stepfamily causes Yusuke to have a mental breakdown, sexually assaulting a woman in public and waiting for the police to arrest him. When he's taken home, he finds his stepmother in the middle of an orgy and begging him to join in, causing him to snap and take a gun off the cops to shoot himself and/or Misako.

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