Chapter 1: Seibetsu Kawaru (♂)

"Fated Partner"

In the world of "The 100 Girlfriends Who Really, Really, Really, Really, Really Love You," a "fated partner" refers to the one destined to be someone’s ultimate romantic match from the moment they’re born.

My name is Seibetsu Kawaru.

After reading the early chapters of this manga, I was reincarnated into this world as an ordinary high school boy (♀).

Why (♀)? It’s just a temporary side effect of some medicine, okay?! But that’s not the important part right now…

Right now, I’m running for my life. Full-on sprinting. Probably one of the most serious dashes of my entire life.

Chasing me is Aijou Rentarou—the protagonist of 100 Girlfriends (or 100 Kano for short), my longtime friend of several years…

…and apparently, my (♀) current "fated partner."

"Wait up, Seibetsu!"

"No way! I ain’t stopping! I—I don’t wanna fall for you, damn it!!"

---

To explain how things ended up like this, we’d have to go way back. Way, way back. A little more—wait, too far! Scroll bar, a little to the left! Yeah, there! Perfect!

It all started… on graduation day. The situation traces back to when Friend A, Rentarou, and I were walking home together.

My Role? Just Friend A+α.

My position in the group? Well, let’s say I’m something like "Friend A+α" when it comes to Aijou Rentarou. Confusing, like a math equation? Yeah, I think so too. All this A and α stuff is giving me a headache… Wait, that’s not the point.

Today was graduation day—the day Rentarou’s fate would change, the starting point of the story. As usual, we were walking home, shooting the breeze with Rentarou and Friend A. Well, after the ceremony, anyway.

"—Cheer Up, Rentarou! So What If You Got Rejected?!"

Friend A, balancing his diploma case on his shoulder, called out to… a depressed-looking Mickey Mouse. Wait, no—Rentarou. His face was scrunched up in misery as he leaned against a telephone pole, sighing deeply.

"Come on! Getting rejected 101 times is nothing! Next time, go for 1,001!"

I gave him a hearty slap on the back, trying to hype him up. Slowly, Rentarou turned around, his expression still gloomy.

"But Seibetsu… 101 times…?""At this point, 101 and 1,001 are the same! Keep going!""...Yeah!"

I flashed him a thumbs-up, and little by little, his crumpled expression started to recover. That unbreakable spirit of his… that’s one of his best traits.

"...Still, it’s a mystery why you keep getting rejected like this."

Friend A stroked his chin, deep in thought. I mimicked the gesture. From my perspective, I get it—but to an outsider, it’s downright bizarre. How can such a great guy strike out this hard?

"Seriously… You’ve got everything going for you, and yet you’re this unlucky in love? That’s not just bad luck—that’s a skill."

"Are you complimenting me or insulting me?!"

Well… I was complimenting him. Maybe. Probably!

"Hmm… An ability that prevents romantic attraction? Like… [UN LOVE - Anti-Romance]?"

"Stop referencing recently-ended Jump manga! You’ll confuse the readers!"

Eh, whatever. Most people will get the joke. If they don’t, they can look it up.

"But seriously, how do you keep confessing after 100 rejections? What kind of mental fortitude is that?"

"And Seibetsu, you keeping track of his rejection count is just as messed up!"

Friend A’s comment made me realize how weird this all was. Yeah, okay, fair. But I only know because of the manga! Not like I can say that, though. If I had to explain…

"Well, this guy did mistake me for a girl and confess to me once! After that, I kinda had to see how far he’d go!"

"Stop digging up my dark history!"

For the record, I do look pretty feminine. If I changed clothes, nobody would think I’m a guy. I’m stuck at 148 cm, with a baby face that makes me look like a little girl. First impressions usually peg me as a tomboy rather than a dude. So, yeah, I get why Rentarou made that mistake back then.

"Heh… Well, at least I’ve got the looks!"

"And whose fault is it that you still don’t have a girlfriend?"

"Ugh…"

…Okay, ouch. Yeah, my appearance is why I can’t get a girlfriend either. Not as bad as Rentarou, but I’ve been rejected a few times—always for being "too girly."

"Guh…!"

"Whoops, friendly fire."

The words "can’t get a girlfriend" hit Rentarou like a sniper shot, sending him back into despair. Friend A and I just laughed. It’s kinda sad, thinking this weird friendship’s ending today.

After that, we kept talking until we reached Friend A’s split-off point. Since Rentarou and I live close, we usually walk home together. Oh, and for the record—Friend A’s going to a different school, but I’m sticking with Rentarou.

"I’ll be watching until the very end… your harem-filled life!"

---

"『Your heartbreak record might grow, but don't you dare kill yourselfー』 huh?"

"Just how much ominous crap does that 'Friend A' need to say to mark a new beginning...?!"

"Relax, Rentarou!"

"Seibetsu..."

"I'll fudge the numbers as record-keeper so your count won't increase! See?"

"You're still operating on me getting rejected as the default, damn it!"

Ahh, this is truly the best. No matter how many times we banter like this, it never gets old. Honestly, this might be what I enjoy most in this life. Teasing Rentarou is just so fun. But still... Soon this guy's gonna build himself a huge (unmarried) family... Assuming the manga kept serializing after where I left off, anyway.

I reincarnated around when Hanakari's mom showed up, so I've got no clue... She probably got saved eventually since it's Rentarou we're talking about, but I wonder how things turned out...?

Here's the real problem. More time with his family means less time to mess around with this guy. And less time messing around with him means... Well... It's lonely, but if he's happy, that's what matters! Alright!

"Heyyy Seibetsu! Keep dawdling and I'll leave you behind!"

"...Yeah!"

Whoops. Got lost in thought and stopped walking. It's fine—knowing him, we'll still find time to hang out somehow. Telling myself this, I took a step forward, trying to ignore the sharp pang in my chest.

"Hey Seibetsu, mind if we stop by the shrine?"

"Love prayer? Sure, whatever..."

Finally, huh? This is where Rentarou gets the whole spiel from the god... But should I really be here? Might there be stuff he can't hear if I'm present? Eh, it'll work out... Even if not now, that god'll probably show up for Koitaro later anyway.

...Or so I thought before getting the living crap scared out of me! Goddammit!

I knew it might happen but I still jumped out of my skin. Let out a totally manly "Hyah⁉" before my legs gave out and I landed on my ass. So embarrassing...! But come on—a face popping out of the offering box? That's terrifying!

I mostly tuned out the god's speech since I knew the gist, and nothing seemed different. Except one thing stuck out—the number of destined partners. Apparently, it's 101 now.

Holy hell. This ain't "100 Girlfriends" anymore—it's 101! Wait, does that mean the number of girlfriends is tied to Rentarou's rejection count?! No way...!

Did I... Did I screw up the whole 100 Girlfriends thing...⁉

...Well, one extra can't hurt, right? I am an anomaly here. A slight deviation was... maybe inevitable.

Oh right, one more thing. Right before we left, the god looked at me and said:

"Thou art... Nay, never mind. In due time..."

The hell's with the cryptic act?! Probably something brewing... but doesn't seem like I'll get answers now. Whatever. More importantly—

"Congrats, Rentarou! 101 girlfriends, huh?!"

"Yeah! If it's true, I can't wait for the entrance ceremony! Hurry up and get here already!"

"...Can't wait!"

......I want to savor every last second of these moments while they last.

---

Today is the entrance ceremony. The day when Koitaro gets confessed to for the first time… or so it should have been.

"Ugh… cough!"

…I had caught a cold.

What the hell was I doing? This was a ridiculously fatal mistake. And not just any cold—no, of course, it had to be the flu. Having lost my parents when I was young and living alone, this hit me extra hard. There was no way I could risk infecting Koitaro, so I fought tooth and nail to cancel any visits.

Don’t get me wrong—I was happy they were willing to risk getting sick just to see me. But wasting such a precious first meeting would’ve been a shame. Somehow, I managed to talk them out of it over the phone, but between "exhausting myself with passionate arguments" and "being too excited about how the Rentarou Family was doing to sleep properly," my condition worsened. And just like that, I completely botched the starting dash of my high school life.

At least Rentarou called me every day, so I knew what was going on. Still, the speed at which his harem grew was downright shocking. First two, then immediately three, then four—it just kept escalating. Even knowing the circumstances, I couldn’t help but be stunned. Like, I knew, but hearing it again made me think, "This is insane, seriously!" Then again, if anyone deserved this, it was him. Kind, considerate, willing to be friends with someone like me… Yeah, I could accept it.

…Anyway. I couldn’t stop thinking about the Rentarou Family. Even if I knew them from the manga, I had to see with my own eyes whether they were truly worthy of him. That conviction only grew stronger with each phone call.

But even after recovering and finally being able to attend school properly, I was swamped with make-up classes for the days I’d missed. By the time I had a free afternoon, the fifth member, Kusuri Yakuzen, had already joined, and they’d survived the "Kiss Zombie Hazard."

Today was the day I’d see them for myself. Sure, my objective might’ve gotten a little sidetracked, but whatever—good enough!

This time, I had a secret plan: a morning ambush! I’d already confirmed that two of Rentarou’s current girlfriends—Hanazono Hikari and Indou Karane—were waiting for him on his way to school. So, if I left with him, I’d be guaranteed to meet them. A flawless strategy, if I did say so myself.

"It’s been a while since we walked to school together, Seibetsu."

"Yeah… Seriously, who schedules make-up classes before morning practice? Cut me some slack…!"

Just like back in middle school, walking to school with Rentarou. Man, I’d missed this. After a while, two figures came into view. Here they come! Alright, let’s see what they’re like!

"Good morning, Hikari, Karane."

"Good morning, Rentarou-kun… and…?"

"Morning, Rentarou… wait."

"Uh… Good morning?"

Hmm… So these were Rentarou’s girlfriends. Seemed like good kids! Yeah! But… what was up with those puzzled looks? Like they were used to weirdness but still found this slightly off…?

After a moment of staring, the blonde one—Indou—spoke first, followed by the pink-haired one—Hanazono.

"Who the hell is this girl acting all cozy next to Rentarou like she owns the place?!"

"Is she… your new girlfriend, Rentarou-kun?"

"NEW GIRLFRIEND?!"

Koitaro and I shouted in unison. No, wrong!

"Wrong! I’m—I’m a guy! Look, male uniform! I’m a dude!"

"Seriously?! You look totally like a girl!"

"…I really can’t see it any other way."

"It’s true, you two. This is Seibetsu Kawaru—just a friend."

Nice one, Rentarou. That’s my guy. Man, I so didn’t see this coming. Being mistaken for a girl was one thing, but his girlfriend? If I were his destined partner, wouldn’t there have been some "zing!" moment when we met? Since there wasn’t, we’re good!

"I thought you’d added another girlfriend…"

"…Well, not that I’d mind."

"Even if my harem grows, my love for everyone will never fade—in fact, I’ll make it even stronger!"

"KYUN…!"

Man, they’re really going full rom-com right in front of me… But man, Rentarou’s just the best, isn’t he? It’s this part of him… So honest, so upfront about his feelings… Yeah, yeah…!

---

And so, after all that, it’s after school.

Along with the two from earlier, I’ve now met the entire current Koitaro Harem—including the petite, smartphone-voice-using "Yoshimoto Shizuku," the ultra-efficient, top-of-the-class "Nano Eiai," and the drug-developing genius "Yakuzen Kusuri."

"[Yet another warrior joins the fray today…]"

"A new girlfriend… is it?"

"No! I—I’m not! Not a girlfriend! I’m a guy!"

"Dating multiple genders at once is efficient."

"[A trap… a maiden among men, perhaps?]"

"No, not a boyfriend either! A friend! F-R-I-E-N-D!"

Hey, quit piling on the toppings—this joke’s getting way too loaded! It’s not gonna last! And I’m not even a trap… or am I? I don’t think so, but… maybe?

"…Anyway, let’s start over. I’m Seibetsu Kawaru. I came here after hearing Koitaro got girlfriends, but… hmm."

"H-he’s staring at us…"

"We were all scrutinized like this at first, weren’t we?"

……Hmm. I see. Just as I thought. No changes in the order they joined, and the number’s the same. Their personalities, too—probably. I get it now. In other words…

"…………As expected of Koitaro!"

"What kind of logic led you there?!"

Huh? Was that really such a weird conclusion? I mean… come on!

"You all seem like good people, and he still won you over… Rentarou’s just amazing! I mean, you all love him, right? And I’m sure he feels the same…"

"W-well… I mean…"

"Yes… I love Rentarou-kun!"

"That’s right!"

"[Indeed it is!]"

"Of course."

"Everyone…! I-I love you too—!"

"KYUN…!" (x5)

Oooh-kay, there they go again. Seriously, Rentarou’s incredible. Even if they are his destined partners, I know—because I read the manga—that this only happened because he took the first step beyond just a "zing!" moment. That’s just… insane.

Well, I’ve seen their faces, so I should probably bail before I overstay my welcome! As I try to slip away from the rooftop, Kusuri calls out to me.

"Wait! I made a new drug, so I want you to test—er, try it!"

"Did rewording that even help?! Shouldn’t you test it with the other first—"

"More test subjects mean more efficient drug trials."

"…Okay, fair?"

I am scared of being a lab rat, but Kusuri’s logic is airtight. Damn it, she got me.

"Then bottoms up!"

"Uh… sure."

I down the liquid in the test tube she hands me. The taste is… BITTER!! I crumple to the ground instantly. This is bad. No way this is normal bitterness.

"It’s way too bitter! So… did anything change?"

"Did the drug fail…?"

Despite drinking it, nothing’s different. Huh? A dud? I pat myself down, but nothing feels off.

"Hmm… Maybe Rentarou should try too!"

Ah, tough luck, Rentarou. That stuff’s just pure suffering—wait, what? The second he drinks it, his body starts transforming rapidly. Is he… turning into a girl? And his hair grows insanely long, covering his eyes completely. This is surreal… So long! It’s practically touching the ground!

"Ah! So it was a gender-swap drug after all!"

[“That shaggy mess… like a primeval jungle.”]

“His hair’s so long he can’t see…! Kusuri-senpai, the antidote, now!”

Whoa. Better burn this into my memory while I can. I won’t get many more chances to see Rentarou acting this ridiculous. If the Family gets any bigger, I’ll definitely be in the way. Hell, I already am. My very presence here is a mistake to begin with.

“Here, drink the antidote!”

I take the vial from Kusuri-senpai and down it—or, well, did I? It’s hard to tell through all that hair…! But in an instant, his locks slither back to normal. Aww, he’s back.

Still, if that drug’s effect was turning someone into a girl… does that mean I’m a girl right now? Huh. Guess I don’t change much either way.

Alright, time to tease Rentarou about his little transformation. That’s what I think—until the second I meet his eyes.

ZING!

A jolt rockets through my entire body. Suddenly, I’m overwhelmed with how much I like the guy in front of me. God, he’s cool. His boyish face is balanced by those thick, manly eyebrows—adorable, but still rugged. And the way he’s looking at me with such earnest eyes—

…Wait.

Hold up.

Hold. The hell. Up.

What just happened?

“Zing! A jolt through my body”? “I like him so much I can’t stand it”?

Okay. Let’s calm down, me. It’s me we’re talking about. Sure, I’m technically a girl right now, but… huh? No. No way. No freaking way.

I can’t stay here. I slam open the rooftop door and bolt into the hallway.

You’ve got to be kidding me. What the hell is going on? I don’t get it. But one thing’s clear.

……Yeah. My (♀) destined partner… is Aijou Koitaro.