This is an English translation of the original Japanese novel, processed through a translation tool.
There may be some inaccuracies.

Link to part 2
https://privatter.me/page/67d4f765cfec5

After it ended, a heavy silence hung between them. The playful banter from before they’d watched felt like a lie.

“…”

Lucifer broke the silence first.
“…Alastor. Be honest. What did you think of that video?”
“What did I think? …It was nothing but unpleasant. I’ll admit I thought you were pretty crass for being able to watch someone else’s sex act so seriously, but…”

“…You watched that thinking it was total strangers?”
“That’s the obvious reaction, isn’t it? There’s no way we’d ever do something that disgusting—not in a million years. The chance of us ending up like that in the future is less than zero.”

“You—! …You don’t get it!!”
“!?”
Alastor blinked in surprise as Lucifer suddenly raised his voice.
What about his words had set him off? He’d thought it was a perfectly reasonable take.

“You can say that because you don’t know how this video got here!! I thought about it too!! …Of course I considered it might be someone else pretending to be us!! But… no… it wasn’t… it was the same!! That man—being fucked, moaning in ecstasy—it was me, without a doubt…!!!”

“…What?”

“…! Everything!! All the spots I love, that feel so good!! The you in the video kept pushing me to climax over and over, knowing I still wasn’t satisfied, and kept going!! He knew every sensitive part of my body, exactly how I like to feel good—he understood everything about me!! …There’s no way—no way that’s a coincidence!!”

“Hey… calm down. This is ridiculous. Whatever the video shows, we aren’t like that now. We’ve got no plans to be, and after seeing that garbage, any tiny chance of it is gone, right?”

“…Haa, haa… I told you earlier, didn’t I? You can’t interfere with the past from the future. The past can’t be changed. …So if it wasn’t guaranteed to happen, sending this video back from the future would’ve been impossible…”

“…Huh?”

“In the near future, you and I will become lovers. And eventually… we’ll end up like we were in that video. It’s set in stone.”
“That’s insane—”
“…Unfortunately, there’s nothing to disprove it.”
“How can you even say that…?”

Lucifer shook his head gravely at Alastor’s trembling outburst.

…This wasn’t good. Alastor could feel his composure slipping in the confusion.
He needed to calm down. Taking a deep breath, he closed his eyes.

“Alastor… are you mad?”
“…No. Sorry, could I have a moment to sort this out? I’m a bit overwhelmed…”
“Oh, uh… sure…”

Eyes shut, Alastor mulled it over quietly.
Lucifer had said that watching the video—seeing Alastor precisely target his erogenous zones—convinced him it was undeniably him being ravaged.
With the added kicker that “the footage could only be sent from a future where this is certain.”

Plus, before watching, Lucifer had said:
“The past can’t be changed.”
An immutable rule, he’d claimed. So there was no harm in watching—it wouldn’t affect anything. Alastor had trusted that, assuming the video was harmless.

“If it’s guaranteed in the future, watching it in the past doesn’t count as changing anything.”

…They’d been careless, completely overlooking the worst-case scenario this implied.

“…”

So that’s why Lucifer had lost it so badly.

And… in their exchange just now, Lucifer Morningstar had essentially admitted to Alastor that he was a shameless, depraved man who moaned like a slut when ravaged by a lover he trusted.
Did he even realize that?

The mere fact that “becoming lovers with this man is certain” was already giving Alastor a headache.

Opening his eyes, Alastor scanned the room. Sorting his thoughts had given him the clarity to reassess his surroundings.
Deliberately widening his field of view, he observed Lucifer sitting beside him.

He hadn’t noticed earlier, but something was clearly off with Lucifer.
His face was flushed, and he was fidgeting, thighs pressed together—like he was trying to hide a heat in his lower body.

“Lucifer… don’t tell me you actually got aroused watching that…?”
“…Well… that’s…”

…This guy. Nailed it.
He seriously got turned on watching himself fall apart so pathetically?
Alastor was dumbfounded. Talk about a masochist.

“Uh, Alastor… sorry…”
“Hey, don’t apologize to me. Are you trying to drag me into your mess? Before arousal, wouldn’t most people feel ashamed seeing themselves like that—or embarrassed that someone else saw it?”

“Embarrassed about being seen, huh…”
“Why do you sound so detached? You’ve got some shame in you, don’t you?”

“…I don’t know. …If it feels so good I can’t think straight, isn’t that enough? Who cares what others think…”
“…!?”

Lucifer’s response was far from sane.

“Do you… even realize what you’re saying right now?”
“…”

…Their eyes met.
The man before him wore the same lust-drenched, seductive expression from the video.
A shiver ran down Alastor’s spine.

…Stop it.
He didn’t want to connect them.
The man in front of him and the depraved figure being fucked in the video.
His mind linked them against his will.

“…The me being held… he looked so happy, surrendering himself… even places I’ve only ever shown my wife, he ravaged so thoroughly, so carefully… feeling that good…”
“Lucifer…?”

…Ah… I’m jealous…

A faint, whispered confession of Lucifer’s true feelings.
Hearing it, Alastor clicked his tongue.

…He understood now.
Why the future Alastor had said that to his past self at the end.
No—he’d been forced to understand.

If the future Alastor shared his mindset, he’d be acting to outmaneuver Lucifer—to wrest control from him.
Defeating the stronger man, dominating him in any form.
As a challenger aiming for Hell’s top spot, Alastor harbored an intense, instinctual desire to dominate Lucifer, fueled by ambition and rivalry.

…It pained him to use it as an example, but even if they became lovers, that core drive wouldn’t change.

The future Alastor must’ve known.
That the past Lucifer, seeing the future Lucifer moaning shamelessly under Alastor’s touch, would undoubtedly get aroused.

That’s why the Alastor in the video had ravaged Lucifer so thoroughly, declaring he’d “handed his past self a gift.”

In Alastor’s mind, he could almost see his future self narrowing his eyes, whispering devilish words with a knowing smirk.

“…If you’re me, you’ll understand.
I’m giving you a chance. …Dominate the strong man before you. Take this pitiful little fool, desperate to drown in pleasure, and fuck him yourself…”

“…Damn it…!”

And Alastor couldn’t—wouldn’t—let this perfect opportunity to seize control from him slip away.

It was infuriating, being played like a puppet by his future self.

But above all…
…Lucifer Morningstar.
This man was the root of it all.
Utterly maddening. If he hadn’t roped Alastor into watching this absurd video on a whim, none of this would’ve happened.
Their mutual understanding, their relationship—it wouldn’t have been shattered like this.

…Unforgivable.
Lucifer’s insolence. His arrogance. Dragging Alastor into his selfish boredom-killing scheme.
The gears of normalcy had been smashed.
There was no way he could stay calm after this.
Everything was the worst.
His wrecked, maddened heart demanded Lucifer take responsibility.

“…Lucifer, you must be suffering, right? If it’s alright with you… I could help ease your pain.”
“…Alastor…”

Wrapping an arm around Lucifer’s shoulder, Alastor whispered the sweet, convenient words he knew Lucifer craved most right now.
…Even if it played right into their future selves’ hands.
Even if it was the absolute worst, most deplorable choice for both of them.

Faced with this foolish man trembling on a platter before him, Alastor had no choice but to devour him.