Inverse Fate: I Get Rewards by Inversing the Heroines' Fates!

Riku stopped the Frozen World and looked back at his former teacher.

"So, Sensei," he started casually. "I didn't expect to see you around here."

Kirisu finally picked the canned coffee, inserting her coins. "I live nearby. What about you? You should sleep during these hours."

"I get bored at home," he shrugged, placing himself next to the vending machine. "Walking helps."

Kirisu grabbed her coffee, cracking it open. "What are you up to these days? College? Work?"

"I'm an accountant now," he answered with a thin smile.

Kirisu raised an eyebrow. "That's good. You do have good records in class for most of the subjects— including mine."

Riku laughed casually. "Thanks for the compliment."

Kirisu took a sip of her coffee, looking unbothered. "Don't mention it."

A brief silence settled between them.

Riku debated testing something. Something small.

"Sensei," he said, watching her reaction carefully. "Are you single?"

Kirisu choked on her coffee.

Riku almost felt bad. Almost.

"What—what kind of question is that?!" she demanded, coughing.

Riku shrugged, keeping his expression neutral. "Just curious."

Kirisu looked deeply suspicious. "Why do you want to know?"

"No reason?"

Kirisu gave him the teacher look.

Riku didn't budge. He had endured her midterms. He feared nothing!

"…Haaah," Kirisu exhaled, rubbing her temple. "If you must know, yes, I'm single. Happy?"

Riku was happy.

The sheer absurdity, the absolute audacity of the system throwing his former world histories teacher into his potential heroine pool? Amazing.

The implications? Terrifying.

The drama? Delicious.

'MILF is the best!'

"What's with that look on your face?" Kirisu shot him a scowl.

Riku blinked. 'What look?'

'Pretty sure my face was just doing its default settings...'

Still, he smiled. "I'm just happy to see you again, Sensei. We weren't close, but I always knew you genuinely cared about your students. You were probably the best teacher I ever had."

Kirisu faltered for a split second. "W-What's with the sudden compliments? You're making me creeped out..."

She probably never had someone saying this to her face 

That was dangerous information. That was lethal information.

And now that he had it, the world would never be the same.

Important note: Riku and Kirisu were not close. At best, she saw him as one of those students who didn't slack off and often asked questions. Their relationship was strictly teacher and student. Nothing more.

But now—

Now, Riku had entered The Point of No Return.

As he processed this, his mind spiraled.

'Setting aside "Minor Inversions," what kind of "Major Inversions" could I even do for her?' He drew a blank. 'Nothing that would result in something positive, honestly… And there's no way in hell I'd ever set her up for a tragic fate. She doesn't deserve that.'

Riku wasn't a villain. He looked like one when sleep-deprived, sure, but his moral compass still pointed in a generally non-evil direction.

'Ugh, if only I could regress with my current mind and body, I could probably give her a proper high school experience—'

…Wait.

'Wait.'

His thoughts screeched to a halt.

'Was that possible?'

His brain whirred as he recalled the system's terminology earlier this noon—Rewrite Destiny, Karmic Extraction, Paradox Blessings, and Timeline Rift.

He hadn't had time to process these terms before, not with the limitations of Frozen World. But now…

"Nifuruji-kun..."

"Hm?"

Kirisu coughed awkwardly, and looked at him with her usual stern look. "...You live in an apartment, right?"

"Yeah...?" Riku tilted his head. "Why do you ask?"

"I plan to move," she said straight away. "And I want to know whether your apartment would suit me."

Riku widened his eyes.

'This is truly a protagonist moment.'

***

...Inside his bedroom.

[ TERMINOLOGY EXPLANATION ]

Riku stared at the glowing interface as text materialized in front of him.

Time to check them.

[ Rewrite Destiny ]

– The act of altering a fundamental event in someone's fate. This is not a minor tweak; this is a complete override of a core event in their timeline.

Example:

–If you were in Re:Zero, this would be akin to forcibly changing Rem's fate so she never gets erased from existence.

–If you were in Attack on Titan, this would mean rewriting Eren's decision to initiate the Rumbling, altering the entire course of history.

–If you were in Fate/Stay Night, this would be like changing Artoria's past so she was never forced into the path of a tragic king.

[ Karmic Extraction ]

– The ability to extract karmic burdens or blessings from a person and redistribute them elsewhere. The severity of the extraction determines the Fate Energy cost.

Example:

–Imagine pulling out the Curse of Hatred from the Uchiha clan in Naruto, effectively breaking the cycle of vengeance.

–Extracting the misfortune that plagues Misaka Mikoto in A Certain Magical Index so she never has to deal with the Level 6 Shift project.

–Stealing Hayasaka's "I must serve the Shinomiya family" duty from Kaguya-sama: Love is War, thus freeing her from her obligations.

[ Paradox Blessings ]

– Each successful Inversion [Major] grants the user a Paradox Blessing, a unique buff based on the new altered fate. The stronger the inversion, the greater the blessing.

Example:

–Undoing Guts' life of torment under the Brand of Sacrifice in Berserk, granting "Beast That Devours Curses" (Passive Resistance to All Curses and Dark Influence).

–Breaking Subaru Natsuki's forced death loops in Re:Zero, granting "Price of the Forsaken Return" (Trade Own Life to Rewrite Any Event Without Consequence).

–Preventing Saber's tragic reign from ending in regret in Fate/Stay Night, granting "Crown of the Eternal King" (Absolute Charisma and Leadership Over Any Kingdom).

[ Timeline Rift ]

– The process of forcibly shifting someone's existence (including the user) into another timeline while keeping their memories, abilities, or even physical age intact. 

Example:

–Sending Itachi Uchiha back in time to before the Uchiha Massacre with all his knowledge intact, letting him change the entire course of events.

–Transplanting Aqua from Konosuba into a serious isekai world, where she actually has to be competent.

–Throwing Light Yagami into the world of Psycho-Pass just to see how he'd handle an actual law-enforced dystopia.

Riku slowly exhaled. "Okay, no. This is insane. This is 'casually defy the entire plot structure' levels of nonsense."

[ SYSTEM NOTICE: Some abilities may have unforeseen consequences. Proceed with caution. ]

Riku stared at the interface, his mind buzzing with all the horrifying and hilarious possibilities.

'…Yeah, this could be dangerous.'

***

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