New mission: Fuck Ponyville.

The next morning...

"Three days," Isaac repeated, his voice echoing in the grand throne room. It took all of his focus not to repeat it like a question, even if it would have probably had little effect.

Both Celestia and Luna reclined on the circular padded podium, looking for all the world like pin-ups inviting the viewer to jerk off rather than royalty conducting business of national importance. Luna glanced at her sister with some skepticism. "Must he leave so soon, though? I haven't gotten him to tire me out like the treatment you got."

"I didn't get his scent embedded into my bedchambers like you did, so I figure that's a fair trade," Celestia replied teasingly, sticking her tongue out at her younger sister for a second. Luna 'hmph'd but didn't take it too seriously. Turning her head to look down at Isaac again, she nodded and said, "Remember how you asked if I had a foolproof plan to help you become Harem Master? Well, this is an important step. There will come a day where we make the big announcement. 'The Harem Master has arrived, and now you all belong to him!' But will it be convincing? Will it be authoritative? Will it give the people of the world confidence? That's the problem that needs to be solved. And there's one solution: Backing from named figures."

"Ahhh," Luna realized, putting a hand to her chin. "You would have him start by wooing the Elements of Harmony. If they back his bid for Harem Master, then who can deny the champions and saviors of the realm? Does he really need three days for that, though?"

"Oh, I have no doubt that our human friend could charm all six of them and their close loved ones in a single day!" Celestia beamed, making Isaac blush at the incredible compliment. "But three gives him some breathing room, lets him take whoever else strikes his fancy in town, really ingratiate himself among the populace while building up his experience."

"I do like taking things at an easy pace," Isaac admitted. "And deadlines with lots of breathing room."

Celestia's eyes hadn't lost their scheming twinkle since the meeting began. "And three days is plenty of time for us to arrange the next phase back here in Canterlot... Introducing you to all the other world leaders. The zebras, the griffons, the changelings, the dragons, the yaks, the hippogriffs... We send out messages that the Harem Master has potentially manifested, and they'll ALL come running here for a summit. Three days gives them just enough time to clear their schedules for a weekend for something so important and urgent."

Isaac gulped. His sense of stage fright was beginning to return. He was going to have to seduce the leaders and royalty of... every nation on the planet. Maybe just a little bit of an escalation! But then again, the potential rewards of having the entire planet declare him their Master...!

Thankfully, both sisters caught onto his ****. "If that's too much, Isaac, perhaps we should scale things back a tad," Luna commented.

"Yes, Isaac, you're an important part of this plan, not just a pawn on my board. What do you think?" Celestia concurred with a warm, sincere tone.

With a deep breath to steady his nerves, Isaac delivered his thoughts. "I'm not opposed to the general idea. But instead of three days, do you think maybe a week or two would be better? I know everyone's in a hurry to confirm the Master, but I don't think I have enough in the tank to give all the leaders of the world the convincing treatment they'll need. Plus, while I'm not worried about seducing all the hot ponies in Ponyville in a few days" - which was a hell of a sentence, Isaac paused to reflect - "but having a bit of extra time will also allow me to relax, take a breather, get some mental space to myself. Rest is a part of preparation, after all - I learned that the hard way back home. That way, when it's time for the summit, I'll be fully ready for it."

"Wisely said," Luna agreed with a sage nod.

Celestia's brow was slightly furrowed. She shifted where she lay, jostling her massive tits. "My only concern is that rumors might spread while you're fucking around that will lead to unwanted public pressure on you and us. My initial idea was to get well ahead of that, make the announcement and set public expectations while we're in control of the conversation." She shook her head wryly, then smiled. "But you're right, avoiding our Master's burnout is far more important. Thank you for standing up for your needs, Isaac. I'll schedule the summit for the second weekend from today; plenty of time for you to have fun and recharge."

Isaac nodded back with a relived grin. "Sounds like a plan, then." He looked down. "Second order of business... Where did I leave my clothes? I took them off in here... Where did they go?"

Celestia and Luna gave each other a nervous, guilty glance.

Thankfully, the royal tailor was able to whip up some new clothes for him, since his old clothes were completely inadequate for keeping his third leg contained anyway. He was now dressed in a loose orange-brown tunic, roomy beige slacks with long white underwear, brand-new socks, and his old tennis shoes (the only pieces of clothing that could be accounted for, strangely).

And just like that, he was back on the Friendship Express bound down the mountain, back towards Ponyville. His 'mission,' such as it was: To meet and fuck Twilight Sparkle, Applejack, Rainbow Dash, Rarity, Fluttershy, and Pinkie Pie, plus anyone else that caught his eye. Some of whom he'd met before, some he'd only seen in passing. They had been lovely ladies before all of his changes with the Root of Harmony, and he couldn't wait to see how they'd changed with all the questions he'd asked - and would continue to ask!

He was currently seated in one of the private roomettes in the back cars of the train. As tempting as it was to mingle with the strangers aboard the train and see what kind of lewd fun he could get into, Isaac felt like it was more important to have some time to himself and reflect on everything he'd done yesterday. (Plus he'd just had breakfast, and the thought of fucking on a moving train made his stomach quiver.)

Abruptly, though, his silence was interrupted by the door opening and someone - a tall, lanky mare? - walking into the cramped panel room with a briefcase and bowler hat. "Oh, excuse me, stud, is this seat taken? Mind if I pop in?"

Then, before Isaac could get a good look at her, she suddenly popped out of existence, her briefcase and hat falling to the floor unceremoniously. Then there was another pop, and Isaac suddenly realized who he was dealing with as she appeared in the seat across from him.

Equine head, deer antler, blue goat horn, lion paw, eagle claw, lizard leg, goat leg, bushy snake tail... impish feminine face, perky brown breasts, slender but feminine hips? Isaac had only briefly met Discord while they were searching for a way to send him home (unsuccessfully), but this wasn't quite Discord - this was his younger female cousin, if anything!

"Isaac~! How's my favorite (and only) human doing, hmm? Finally worked up the nerve to start draining your dick, hmm?" she teased him.

For his part, Isaac was a little too stunned and worried to speak for a few good seconds. Here was a creature with phenomenal cosmic power almost a peer to the power he'd recently acquired. If anyone had a chance of stopping his irresponsible cosmic sexual rampage, it was... her?

"Awww, c'mon, horse pussy got your tongue? It's me, Eris! Goddess of Chaos! Remember?"

"Y-Yeah, I remember," Isaac murmured, heart racing and cold sweat beading on his shoulders. So at least his questions had affected him, and Discord, formerly male, had taken the gender-swap route. That was a significant confirmation that his questions had really affected reality outside Canterlot, even though he'd been fairly sure before. Now for the million-dollar question: Was she just bothering him to be annoying, or had she actually noticed his reality-warping and was here to figure him out and get **** if need be?

Discord- er, Eris pouted indignantly and folded her arms. "Oh, I see how it is. You got a taste of the high life and now it's all, 'Oh nooo, Eris is gonna flip the tables and ruin my fun. What if she transforms me into a newt or part statue and I never get to fuck anyone ever again?' That's what you're thinking, right?"

Deadass. "I'd be lying... if I said no..." Isaac replied slowly with a strained voice, his eyes darting back and forth.

"Bitch, lemme tell you something," Eris growled, startling Isaac that her demeanor had changed from ancient trickster to impish brat. She floated up into the air and pointed a clawed finger at him. "I put a lot of work into that Family World business specifically so that this planet can be 100% porno all the time without any uncomfortable ethical issues! ...And also to satisfy a passing interest in rapid-maturity ****, but that was secondary! So I better hear some words of appreciation!"

Isaac put his hands up defensively. "I'm immensely grateful! That's a big worry off my mind!"

"Damn straight." Eris floated back down into her chair, her legs crossed in front of her plump, furry brown pussy. "Sure, I've got phenomenal cosmic powers - I don't need a Harem Master as much as these other sluts. But dammit, it's like having the same program on a thousand TV channels - this world needs a change-up (that won't destroy it), and you're the best shot at that! So I'm on your side, buddy - geez!"

In a flash, Isaac was struck with inspiration and a potential test of their relative powers. "So you're basically a cosmic voyeur treating this world like your personal porn network?"

"Only the creatures that get up to sexy shenanigans outside the privacy of their own homes - which is like all of them," Eris clarified with a slight smirk. "Public areas of the palace count, too. And heck, Celestia and Luna and I go way back, so they probably won't mind that I watched you turn them into your cock-worshiping whores."

The way she phrased that, it made Isaac reeeally wonder if Eris knew about the Root of Honesty. It seemed like she was just as affected by his changes as anyone else, but with a millennium-old trickster, there was also the chance she was playing her cards incredibly close to her bare chest. Still, the last thing he wanted was to start a confrontation that became a high-noon reality-warping quickdraw showdown, so his instincts told him to play along instead. "Well, can't say I'm that much of an exhibitionist, and I value my privacy and quiet time. But if I'm doing stuff in public, I guess I won't mind knowing you're probably watching. You'll respect my boundaries, right?"

"Yeah yeah, sure sure," Eris dismissed him with a wave, giving Isaac some nervousness as to whether his question had worked or not. Then she leaned in with her hands beneath her chin. "That's not what I came here to talk to you 'bout today."

Isaac took a deep breath and leaned back in his seat. "Okay, then what?"

"Two things. Actually, just one thing for now, one important thing; we can talk about the second thing another time. First off, I want to know what secret you're hiding," Eris said rather pointedly with a cute grin, making his heart hammer in his chest. "You know way too much for an alien. You somehow always know what to say to make those stuck-up bitches swoon for you. What kinda secret are you keeping from those lovely ponies you fucked?"

Isaac swallowed hard. So she might not know for sure what was happening, but she definitely suspected something, and she wasn't going to leave him alone until she got a satisfactory explanation.

But if he told her about the Root of Harmony... Would someone as prideful as her stand for having her existence rewritten at his whim? Not without changes, certainly, but he didn't want to try and create a situation where he put rules on her that she could chaotically wiggle out of. That was a hubris trap if there ever was one.

Then again... he wasn't just carrying one secret...

"Weeellllll~?" Eris crooned, the centers of her mismatched eyes growing slightly red from impatience...!

"Okay okay!" Isaac relented, putting up his hands. "The truth is..." He gulped and looked out the window of the train, viewing the plains from the cliffs the train was running along. "I recognize a lot of this world from... a TV show back home. The people, the places, the characters, even you. For some reason, this world is a lot like a cartoon that I used to watch. I have no idea why, but I haven't told anyone."

Eris pulled back a little and sloooooowly raised an eyebrow. "Really. A cartoon. With this much blatant fucking happening everywhere?"

"Alright, it's not exactly like the show, not by a long shot. More like... a porn parody of it, somehow. I don't know how it's possible or if there's any correlation, but the names are the same, the basic personalities are the same, the lore and setting are basically the same... with some differences..." Isaac shook his head. "I just don't know what to do with any of that knowledge."

And it was the truth. How could he, a huge nerd, not notice that he'd landed in a world of anthropomorphic My Little Ponies? But he'd felt a need to keep it secret. The whole Root of Harmony had thrown a huge wrench in his understanding of the world, but other than that, everything was... Well, not quite one-to-one, but definitely around one-point-five-to-one.

That was before all of his pornographic changes, of course.

Isaac suddenly realized that Eris now possessed a stethoscope and was pressing it against his chest, looking up to the side and listening to his heartrate. Taking the earpieces out of her... horns(?)... she pouted in thought and said, "Well, all signs point to telling the truth. That would definitely explain how you just seemed to 'know' the Princesses so well..."

"You believe me, right?" Isaac said a little too quickly. "You don't think I have any other big secrets to hide, right?"

Eris got in VERY CLOSE to his face, her eyes staring into his. Staring into her yellow sclera, Isaac felt like he could almost see embers, like her eyes were lakes of fire...!

Then she backed away, and Isaac could breathe again. With a shrug, she said, "Yeah, now you're just a normal big-dick nerd who got extremely lucky. Which is perfect for this world, yeah, but, y'know, it's a whole trope that's been done before, right?"

Isaac couldn't argue with that. But he could try to make her more engaged. "For a being like you, there's nothing wrong with the classics, no matter how many times you've seen them, right?"

Eris chuckled with a long-fanged grin. "We'll see! This show's only getting started." She then slid off the seat like water and re-formed in front of him with her hat and briefcase. "Happy fucking~!" With a snap of her fingers and a flash, she was gone.

At last, Isaac allowed himself to release the tension in his chest, slumping in his seat. He felt like he'd just dodged a whole magazine of bullets. And even after deflecting her suspicion, Isaac was left feeling like he needed a long-term solution for her down the line.

After watching the cliffs roll by and seeing Ponyville down below get steadily closer and closer for a while to clear his mind, Isaac finally landed on the idea that he hoped would make Eris more fun for him in the future. Speaking quietly against the glass of the window, he asked,

"Will Eris eventually realize that she deeply, truly, and genuinely wants to become my personal genie, granting me unlimited lewd wishes to reshape the world as I see fit, getting off on encouraging me to explore my kinkiest ideas?"

Even though he couldn't see the effects of his question, Isaac grinned as the Friendship Express pulled into Ponyville's station.