Chapter Text
“So he gets pregnant. This guy.”
Such were the words of my online friend when I sent bloodline to him, along with a few pictures of Sanemi. Granted, the images weren’t flattering, but the utter shock of it stands. Anyone who’s read or watched Demon Slayer would find the whole concept absurd. Anyone who simply sees Sanemi would laugh or think I was a loon.
Even on Archive of Our Own, a pregnant Sanemi is rare. Astonishingly rare, at least, compared to the rest of the cast. By contrast, a brief search on the site shows that “Pregnant Tanjiro” is common, and Giyuu was named 45th from the top [1] to be made an Omega in stories. Moreover, among the 91 fics that feature mpreg-Sanegiyuu, only 7 knock up Sanemi. Above all, besides bloodline, they occur outside of canon.
Given this, we can conclude a few interesting things. First, Sanemi is more sire than carrier. This is very clearly due to his hyper-masculine persona, as well as his propensity for aggression. Second, should Sanemi carry, it would be unrealistic in canon. No way would he bring forth a child as himself. Nevermind that other contenders in fics would also choose abortion; Sanemi specifically would kill it. His canon role is too vicious, too coarse. Pregnancy would not be viable.
Hence, to successfully pull off bloodline, these issues must be resolved. If not solved, they must at least be addressed. Otherwise, the premise fails. In this essay, I pose bloodline works because of three main stages - sickness, starvation and sacrifice. Each helps suspend disbelief at male pregnancy, while keeping Sanemi in character.
Sickened
The biggest hurdle to selling bloodline is Shinazugawa Sanemi himself. His character is diametrically opposed to pregnancy. Within the cast, he is the most hostile and also the most masculine [2]. Meanwhile, pregnancy is conventionally female [3]. This gives rise to extreme dissonance; it is terribly easy to feminise Sanemi by virtue of being knocked up, but that would shatter reader disbelief. To preserve it, one must keep him a man, and also keep the child.
For Sanemi to be distinctly male, one must rely on his language. He is, after all, an illiterate soldier. Not only must his words be less than three syllables, it must be recognisably man. Seeing this, I cannot employ my own high-register vocabulary. Instead, I pivot to other techniques:
Too slow. He’s too fucking slow.
Bloodline is repetition-heavy. This has a few purposes. First, it adds to the feeling of panic; his thoughts are now closing in. Next, it allows for emotional intensity without having to use bigger words. Finally, it lets him stay in denial while also betraying reality - the soldier simply doth protest too much. I suspect Sanemi’s denial is what truly sells bloodline. If the reader cannot believe it, neither can he.
Repetition is also assertive, for it implies forcefulness. This is seen more commonly in men [4]. In fact, men are more deigned to use hard expressions, leading me to my next point:
Slide it left. Walk inside. Sit the hell down.
Sanemi, and by extension the Corps, is defined by his commands. It is thus obvious that he relies on them, especially when his mind fails. Orders and imperatives tie him to soldierhood, keeping him a man or weapon first. Without them, his identity slips into that of a parent. Together, these two literary devices make up a mask of control, even as we realise it is slipping. They evoke a masculine tongue [5] - a military tongue.
What else, other than language then, to enforce the male condition? Perhaps how pregnancy is portrayed itself. While later stages of gestation are recognised as woman, this is less so in the early periods. It is possible to interpret morning sickness as persistent vomiting, or something that resembles illness. Illness, unlike pregnancy, is read as gender-neutral, and is infinitely more relatable. Hence, with Sanemi violently sick, one bypasses disbelief.
It also explains why the child is not killed; he is too ill for an abortion. By the time he recovers, attachment has formed, and he kicks the can down the road. Moreover, mental illness and trauma heavily influence Sanemi’s choices:
He watches it fall, plummet hard like a stone -
You killed her! Murderer! You murderer!
Suddenly, it dawns on me how obscene bloodline is. The guy who committed matricide is carrying a child. With this seed, I can plant the idea that Sanemi will keep the kid, not because of sentiment, but because he cannot kill it. Abortion, whether he knows it or not, hits his deepest sin.
“Oh, Shinazugawa-san... Don’t cry.”
Beyond illness, there is something symbolic about Sanemi vomiting water - the very element of his mate and sire. Not only does he sick it up, it leaks out of him. Water is shorthand for Tomioka Giyuu, and the man physically rejects him. Yet, since both vomit and tears are his, Sanemi cannot escape him.
Given this, Sanemi turns on himself. His violence redirects inwards. As he tries in vain to purge Giyuu from him, pregnancy is viewed as conquest:
Idiot bitch. His eyes water. He stares at his stomach, at the mound of skin.
Occupied.
He’s being filled.
It is no mistake that “occupied” is the word Sanemi uses. As a soldier, he is not new to invasion. By referring to himself as “fucking terrain” or “a mass of earth, hanging there”, he distances himself from his body. By using the language of colonisation, he comprehends on his terms. Furthermore, the passive voice “being” adds to his profound defeat, while the use of continuous tense deems surrender a process. Notably, female metaphors are absent; there is nothing on love or creation [6]. Instead, pregnancy is equated to war, thus making it masculine.
Overall, this wartime logic permeates the text. Demon Slayer is a battle Shōnen. It is hence understood that Sanemi is aggressive, even to his detriment. Should readers still refuse to believe, they must at least see him fail. And fail he does, in great, terrible ways.
Starved
Sanemi is violent. In fact, he is rather notorious for it, having stabbed one of the leads. This is, in some way, a kind of starvation. Not a physiological one (though he suffers that too), but one of emotion and relation. This is a man so convinced of his hate that he blocks out the people he loves, even as he drives towards his death. This makes loss of strength believable.
One of the problems with writing bloodline is selling Sanemi’s duality. He must be both villain and victim. Part of the reason I chose him for this was due to how badly he fit; he is anything but a pregnant omega. To work, I must construct a logical link between Sanemi’s vulnerability and aggression. Given this, I look to the good Bard.
Caliban, from Shakespeare’s The Tempest, is more of a creature than man [7]. I had written a paper on him years ago. In it, I argued that while he was wicked, Caliban was too naive to execute evil. Hence, both traits could coexist inside him. Likewise, the nature of Sanemi’s rage is highly defensive and cyclical. He is weak, and so he is fierce, which weakens him further.
So violent is this impossible man, that he bestows it on his brother. Consider how he perceives Genya:
Wreck. Whelp. Wretch. The boy whimpers.
The “W” alliteration conjures wickedness (thank you Michelle Yeoh), while the rule of three cements it in. “Wreck” displays the state of their bond, and “wretch” describes how ruined. However, what is most notable is Sanemi’s use of “whelp”, which could mean a young boy or a puppy. Since this is Omegaverse and children are known as “pups”, wonder what that says about Sanemi.
Also consider what Genya is called when he cries out in pain. Rather than harsh insults or swears, he is just “the boy”. Yet, the child fails at staying a child:
“Useless fuck! WHAT DID YOU DO?”
Instead, the balance of power shifts. Genya is now an alpha. He has grown out of needing “Nemi”, and can stand on his own. Still, Sanemi is horror-struck by his brother’s newfound strength:
All he had done to kick him from the Corps, and Muzan still managed to touch him.
Genya’s power, borrowed from demons, is biological contamination. Just as Sanemi is cursed to carry, he is cursed to sire. As Genya’s words pivot to protection, Sanemi feels himself slipping. Violence, then, reclaims what is lost - it brings back agency. Even so, this last - ditch attempt to “save” Genya costs him:
The brat is gone. The wretch is gone. Genya is gone. Good.
The earth tilts.
Genya very nearly kills his brother. Yet tragedy lies in how Sanemi falls after making sure Genya has left; he cannot be seen weak before him. By the time Sanemi sees Genya again, he is considerably sicker. Violence has eroded his wellbeing. He has chosen this path, as his brother chose his, and that is the path of starvation. This time, Genya has no heart for him.
Giyuu, on the other hand, is poisoned by narration. Sanemi’s lens is unreliable. Often, Sanemi’s opinion of Giyuu does not reflect reality:
Tomioka Giyuu looks full of himself. Shallow eyes, filled up with nothing.
Given that Giyuu proceeds to clean up, this judgment is clearly false. Yet, through Sanemi’s myopic view, his lack of tact looks like pride. While this dynamic is aligned with canon, it is catastrophic here. Quiet is misread as abandonment, reticence as negligence:
“Shinazu-” Tomioka swallows, voice hoarse. “Shinazugawa, you smell like me.”
This line is both objectively plain and subjectively disastrous. With Sanemi knocked up by him, it sounds like an ownership claim. More statements like these can be found in bloodline, in contrast with Giyuu’s actions, from “Am I hurting you?” in Chapter 5 to “No” in Chapter 7. Giyuu’s lines are vague by design, so they hold multiple meanings, and Sanemi (by virtue of being Sanemi) often assumes the worst. By sheer lack of social skills, Giyuu is made cruel, and this adds to Sanemi’s despair.
By turning a blind eye to reality, Sanemi continues to starve. Shinobu explicitly tells him that. The medical aspects of Omegaverse make bonds a biological need:
“Keep at it, and you’ll develop bond sickness. You need Tomioka-san, badly. He’s not a smart man, so you would have to yell -”
“I’d rather die than talk to him again.”
In pursuing agency, Sanemi loses it more. By refusing others’ care, his autonomy fractures. In canon lore, the price Sanemi pays is losing Genya forever. In this world, the price that he pays is his body. Even so, this rejection is vicious, which helps him stay in character. Sanemi will fully make good on his threat, sending him straight into hell.
In the end, Sanemi is starved through violence and misalignment, making his decline believable. His rage and fear make up what is called a positive feedback loop [8]. He is frightened, so he lashes out, which drags him down even further. There is only one way this can possibly end, and that is…
Sacrificed
Sanemi is suicidal. I will not explain why and how this is so - this man bleeds his arm for a living. Even while pregnant, this urge will not change; in fact it probably worsens. For a man defined by physical prowess, his body is his one asset. Now that it has started to rot, this scenario happens:
Suddenly, Sanemi thinks about falling. He lifts a hand, thinks of his feet. What would it feel like to step on the air? Plummet down, wind going through him?
Sanemi is the Wind Hashira - a master of aerial movement. It is thus ironic that his suicidal thoughts cast him at gravity’s mercy. As he gives himself over to his element, he condones his own erasure. Soon enough, this dark wish comes to bear fruit:
“Pregnant marechi! Does the sire know!”
Sanemi plummets.
The plunge imagery now bleeds into battle as Sanemi crumples face-down. This time, he is helpless to stop the fall. Rather than a sacrifice, it reads like a jump. Dying becomes physical and symbolic. First, there is the bodily death - Sanemi is truly injured. Next, there is the Hashira death - the end of his martial career. Finally, there is the death of the mind - he cannot stay in denial. In saving the great Tomioka Giyuu, Sanemi loses his nature.
It is highly difficult to imagine Shinazugawa Sanemi a victim, especially when he constructs his fall. For most of bloodline, he does not act like one, appearing more like a villain. In fact, he dons a monster persona that he mentions in monologues:
Monster. Shinazugawa Sanemi is a monster. That was how things always worked. But monsters don’t bleed, don’t fall over like this. Don’t crumple, don’t collapse, don’t ache.
While this is a show of dehumanisation, Sanemi still remains whole. This line is more to establish the clash between both his roles, past and present. There is the role of Sanemi the fighter - a violent and vengeful Hashira, and there is the role of Sanemi the father - a broken guardian figure. The tragedy of Sanemi’s arc is how his rage has been rewarded, when it ends up costing him his brother. Now that monstrosity has failed to work, Sanemi’s worldview crumbles. It starts to crack, then decays under strain, until at last there is this:
Monster. Shinazugawa Sanemi is a monster. Monsters do not get to live. They’re killed, and there is nothing more left to it. That’s just the way the world is.
Sanemi’s dehumanisation is a coping mechanism. By denying personhood, he can pretend not to feel. He can pretend to not want, fear and need, and can keep being a weapon. Worst of all, he fools the world and himself that his life is disposable, even when a child grows inside him. At the core of Shinazugawa Sanemi is a man who thinks himself a monster, thus justifying his annihilation. After all, a man dying is tragic, but a monster dying is triumph.
Adding to his martyr complex is Sanemi’s will to die useful. He perverts a children’s tale to show this. The Official Demon Slayer Fanbook lists Naita Akaoni [9] - or “The Red Oni Who Cried” in English - as an influence for Sanemi. In bloodline, the myth is taken further. As Sanemi tries to save Giyuu, the narrative plays out, ending in the Red Oni’s defeat. He sets himself up as the beast to extinguish:
Rabid dog. Dying beast. No longer human.
Animal, to be put down.
Yet Sanemi is worlds apart - his state as carrier is precious. Thus, it is to everyone’s horror that he suffers the final blow. Sanemi also realises later that he recalled the folktale wrong, and has inverted the roles of both demons. This explains his unreliable nature, and also demonstrates his grief. So badly does Sanemi want to die clean that he twists the tale to suit him. Alas for him, he now has to live dirty.
Still, how did Sanemi get to this state? One does not plummet alone. Though Sanemi's downfall is caused by himself, others are also complicit. Consider the reason why nobody helps after Sanemi is humiliated publicly:
“They want you to do it, Shinazugawa-san. They’re giving the choice back to you.”
Choice is a central theme of bloodline, yet it serves to punish him here. By letting Sanemi keep his pride, the Slayer Corps dooms him further. For all they care, this is a private matter, and they have no responsibility. Given that Sanemi is highly ranked, this neglect appears abhorrent. It also lets him deteriorate more, ending with the fatal mission:
“CAW! TOMIOKA! SHINAZUGAWA!”
It starts coughing. It hacks and chokes, drooping against the ground. The oldest crow known to man. Shedding its feathers, it gives a small hop. It topples, beak in the dirt.
Even if Giyuu’s crow is old, this imagery is significant. As a Corps symbol, it is decrepit - a rotting farce of an organisation. The shedding feathers resemble decay, the toppling foreshadowing. Just as they send a sick crow with a message, the Corps sends a dying soldier. By the time Sanemi collapses face-first, the deathblow has taken place. By then, the upside-down kanji for kill does not refer to a demon.
What is going to war while three months pregnant, if not an act of suicide? What is sending someone three months pregnant, if not an act of murder? Of course, one can certainly argue that this is expected for Corps life, but a child is also a bystander. Rather, everything points to institutional failure. All in all, this sacrifice concludes bloodline: part one. It bridges vulnerability in pregnancy. By exploiting his flaws, the stages add up, finally knocking him flat. With him broken down enough, softness seeps in, setting the stage for redemption.
Any story, no matter how strange, thrives if linked to the human condition. In bloodline, this humanity shows despite Sanemi’s efforts. It is easy to write a monster, much harder to write a man. I intend to keep Sanemi a man, even as bloodline progresses.
Bibliography
[1] Wolf. “Omegaverse Fanatic — Ao3 2025 in Review: Omegaverse Edition.” Omegaverse Fanatic, 2025. https://theotherwolfinsideyou.tumblr.com/post/805207966900011008/ao3-2025-in-review-omegaverse-edition
[2] BlacLionfang and leytourmaline. “R/Kimetsunoyaiba on Reddit: To the People Who Hate Sanemi.” R/Kimetsunoyaiba, 2022. https://www.reddit.com/r/KimetsuNoYaiba/comments/syag7s/to_the_people_who_hate_sanemi/
[3] Binarythis, Hannah. “Woman Culture and the Gendering of Pregnancy.” BINARYTHIS, October 24, 2021. https://binarythis.com/2021/10/24/woman-culture-and-the-gendering-of-pregnancy/
[4] prince. “Gender Differences in Vocabulary: How Men and Women Express Themselves.” Public Administration Institute, December 13, 2025. https://pubadmin.institute/gender-sensitization/gender-differences-in-vocabulary
[5] prince. “How Gender Influences the Use of Imperative Sentences .” Anthropology Institute, December 16, 2025. https://exploreanthro.com/gender-sensitization/gender-influence-imperative-sentences/
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[7] Bevington , David. “Caliban | Prospero’s Servant, Monster | Britannica.” Encyclopedia Britannica, 2026. https://www.britannica.com/topic/Caliban-fictional-character
[8] Hally, LiLin. “How to Escape the Anxiety Feedback Loop.” Abri Psychotherapy, August 20, 2025. https://abriradicallyopendbt.com/how-to-escape-the-anxiety-feedback-loop/#:~:text=What%20Is%20an%20Anxiety%20Loop,the%20cycle%2C%20not%20feeding%20it
[9] Yoshie. “Naita Aka Oni.” Naita Aka Oni, January 1, 2006. https://montages.blogspot.com/2006/04/naita-aka-oni.html