Hearts Shadow was enjoying a light snack in his laboratory when he heard a pony knocking on his door. Considering where on the door it was coming from it was a foal.
As he got up to answer the door he heard some mumbling followed by a slightly familiar, if higher pitched, voice yell "I AM THE SUN!" at whoever they were argueing with.
His interest piqued the warlock opened the door to find a filly Celestia standing in front of it.
"Discord." She stated in answer to the obvious question. "Can I look over some of you notes? I want to figure out all my options for retaliation are."
"Sure." He replied, stepping to one side so she can enter.
As the filly princess trotted over to the desk he returned to his snack. She glared at the height of the furniture before moving a stool over. Jumping up on the stool only brought her to eye level with the surface requiring her to rear up and place her forehooves on the edge of the desk.
Looking over all that was on it she noticed a small card sitting half on the edge, teetering over a trash can. Floating it up in her magic she saw that it was a party invite from Blueblood for a masquerade ball on Nightmare Night. Raising an eyebrow she placed it back where it was before returning to her original task.
Some time later as she poured through book after book, a noise drew her attention. Hearts Shadow had been fiddling with some potions when he had remembered something.
"There's a kind of rock that is supposed to absorb magic, if you attuned it right, you could put him in a cage for a while. Though that would take a lot of material." He said, turning toward the youthened Celestia.
"If I shrunk him down first, but a cage would be too much. Maybe a bracer then. Yeah that would work. Thanks for the help." She said jumping down and running over to the door. Opening it with her magic she darted off to another place in the castle to plan her vengeance.
A proper sized and aged Celestia met Hearts Shadow for tea a couple days later. A diminutive Discord was serving them as they chatted. When the conversation turned to their plans the invite she had seen was brought up.
"Normally I get invites to all the parties that the nobles throw, but when I talked to my steward he wasn't aware of Blueblood's. Odd that he of all the ponies wouldn't send one to me." Celestia remarked.
"Likely he plans on trying to humiliate me. I don't like dealing with stuffed wig nobles, so my attitude towards him has put him off on me. Granted, my own actions aren't exactly subtle, but he has imagined slights on a few of the times we have met. Like my little adventure with Twilight, our frequent tea-times, and my occasional discussions with Luna making it seem like you all prefer me over him." The warlock said, sipping his tea.
"I'm rather tempted to put on a disguise and go to that party. Luna would be at Ponyville for her usual antics so I have some time to spare before we meet up and enjoy the night as sisters." She stated.
"Hmmm. I wasn't planning on going, but it might be fun to bring you along actually. Would be fun to see his plan fall flat in his face, then get lectured by you on proper behavior and whatnot." He mused.
They continued to scheme for the rest of the snack, with one or two quick quips from Discord before he offered to transform Celestia for the duration of the party, if she took off the bracer keeping him small.
Nightmare Night came around and Hearts Shadow had finished getting into his outfit. While the invitation stated to wear a costume, he had wisely reached out to some of the other ponies going and confirmed that a formal outfit and mask was what theirs had said. Of course Celstia, temporary turned into a pegasus named Sunny Skies, was wearing a dress as part of her fairy queen costume.
Their plan was for him to be the proper noble while she was a commoner playing at being proper. Her wearing a costume instead of a more formal outfit helped sell that image.
The warlock left his quarters and walked over to Celestia's to pick up Sunny for the party. She met with him promptly and they began their way to Blueblood's mansion.
After being let into the house the pair were heralded as "Hearts Shadow, Earl of Equestria and Warlock of the High Order, and his date."
Moving down the stairs they joined the ponies milling about waiting for the party to officially start. As they meandered about most of the nobles gave them a slight berth signalling disinterest in chatting with the pair.
The warlock and Sunny were just fine with that, chatting with each other to fill in the time. Eventually even the fashionably late ponies had begun arriving.
Hearts Shadow noticed Blueblood off to one side, whispering something to a servant. A few minutes later a couple ponies began weaving through the crowd, trying to keep their destination from being obvious. They set themselves apart from the drink servers by having trays of finger food with them and most of the nobles they walked by ignored them.
When the servers got around to him it was clear that the point was for him to take the food early as they actually offered the contents of the trays to him instead of just walking past. As he was about to pretend not to notice them, Sunny Spoke up.
"Oh, that looks scrumptious." She stated, moving a wing to take some of the small food items.
"Allow me dear, don't want your lovely dress to be ruined." Shadow offered, floating a couple of the appetizers off the tray and over to her.
"Thanks." She said, before taking a bite.
"My this is wonderful. Though I have to ask why no one else is having any." Sunny remarked once having eaten the first of the items.
"Well, normally one would wait til after the host had officially greeted and started the party. No idea why they started the appetizers so early." Hearts Shadow said loud enough for the nobles slyly watching him to hear.
The servers quickly moved off before hoping to avoid any ire, however they did return to the kitchen with empty trays.
As Sunny ate the food Shadow held for her in his magic, they were finally approached by some of the other guests.
"I have heard about you Mr. Shadow, but you do seem far more civilized than what rumour has to say. Your date for the evening is quite the sight as well." Stated the somewhat elderly unicorn stallion, bowing to Sunny.
"Most do tend to associate Warlock with some sort of vile pony bent on evil doings." The warlock replied.
"Thank you for the compliment. Shadow here offered to bring me here when he ran into me sulking about the castle due to my niece being sick. I was going to take her around town for candy." Sunny said with a wistful tone to her voice.
"I hope she gets better. Tis a shame for a young filly to be unable to enjoy a holiday. Make sure to pick her up some-" The unicorn said, before being interrupted by Blueblood.
Standing on a landing of the stairs the host said loudly, "Hello. Welcome to my modest home. I hope that you all enjoy tonight's festivities."
As he moved down to join the guests the servers returned with the appetizers. When they passed Hearts Shadow he snagged a few more for him and Sunny.
Now that the music kicked up to something more than just light background noise the nobles were more willing to enjoy each other company.
"This is a lovely dance tune. Come on Shadow." Sunny stated before dragging the warlock out on the dance floor.
Some time and several dances later they were in conversation with another couple.
"Is that the mark of the royal tailor on your dress?" Stated a mare joining the group.
"Oh yes. I deal with the bureaucrats at the castle and managed to weasel him some vacation time when his grandfoal was born. I called in my favour to get this dress done quickly." Sunny explained.
"I'm jealous. It's extremely rare for him to make anypony anything if they aren't an alicorn." The newcomer remarked before the conversation turned to fashion trends.
Hearts Shadow smirked at that and listened to the stallions he was standing next to talk about some of their businesses. When they eventually asked him about his going-ons he quickly had them enraptured with his tale about the temple he had visited to keep a demon sealed away.
When Blueblood's rounds of the party lead him to the pair's group Shadow was discussing the details of how his blight worked while Sunny had the mares talking about the foals in their families.
Keeping his face straight, with the exception of his eyebrows which showed his frown, Blueblood joined the group.
"So by feeding off the lifeforce of what it infects, the blight generates more power. So the larger the area it covers, the power needed to clear it increases by a factor of 3, unless there's a mountain in the area, then the exponent is a 4." The warlock said.
One of the unicorns whistled at that before saying "To push that much power through the ground you'd need pretty much every magus and archmagus in Equestria."
"Which is why you pair the unicorns with earth ponies. Their natural magics grant them a connection to the land which almost halves the amount of power you need to generate before channeling it." Shadow replied.
"Is that why you joined the cannibals then? To acquire you blight?" Blueblood asked.
As the other stallions balked at hearing the word Shadow just smiled. "No actually. I joined their tribe to gain access to some bones they held as sacred. While even I don't know the name of the creature, it resembled a turtle judging by the skeleton. The fact that even after ages of being dead the bones still had magic coursing through them intrigued me and was why I wanted to study them." He explained.
"So you became a cannibal to study a turtle?" Questioned the party's host.
"I became one so I could get a better sense of how other creatures are connected to the magic of our world. It was of an immense aid to my primary project." The warlock said.
"Wait, you actually are a cannibal? As in you ate another ponies flesh?" One of the other guests asked worriedly.
"I partook in their rituals so yes to both. Though I haven't since I left them as I found the taste to be... well distasteful." Hearts Shadow said with a reassuring smile.
Before much more could be said Sunny Skies dragged him off for more dancing. Blueblood walked off to mingle with other guests, smirking at how he figured the nobles would react to the warlock's words. This meant that he missed their actual reaction as they judged him more off of how he was while talking to them rather than actions taken over a thousand years ago. If they could accept Luna despite the actions of Nightmare Moon, they felt he deserved a chance as well.
As the night progressed Hearts Shadow avoided several other subtle attempts by Blueblood to have him humiliate himself. While Celestia relished the opportunity to have fun and find out what the nobles say when she wasn't around not caring how they viewed her. Her attitude causing several of the other nobles to have more fun themselves even leading to some triggering the tricks meant for the warlock.
As the night started to come to a close the host decided to try one more, less subtle attempt. He had brought in several illusionists to help him with this, knowing that if a bunch of demons were to show up and other nasty things were to happen, he could easily blame it on the warlock and ruin him.
Blueblood trotted back up to the landing and drew everypony's attention. "I do hope you all have been enjoying my party. I'm aware that several of you have other plans you might want to be getting to so lets wrap this up with the unmasking so you can -" He said before being interrupted by the light all going out.
Several large monsters burst forth from different areas of the room scaring the various nobles. Many mares screamed, as did several stallions who sounded just like the mares. This was followed up by some of the guests discovering they had been partially transformed as hooves and horns became tentacles and wings turned into legs.
As the nobles freaked out and trampled each other to try and reach safety, injuring one or two others, Sunny Skies sighed. Blueblood was waiting for the mayhem to reach maximum before blaming Hearts Shadow. Celestia turned her disguise off and used her magic not only to relight the room, but also dispel the illusions.
The chaos died down quickly and the nobles stared at their diarch standing next to the warlock. She locked eyes with the host before sighing with disappointment at him. Looking around she used her magic to help up the poines who had fallen over, healing the ones who had gotten hurt.
"Luckily it doesn't seem anypony got seriously injured. Blueblood, I would like to talk to you tomorrow in regards to this. I know it's Nightmare Night, so scaring pranks are a bit more okay, but this was taken too far. Hopefully none of your evening are too badly soured by this, I know my sister would be sad if everypony was unable to enjoy her night." Celestia said, her voice smoothly switching from reprimanding to reassuring.
Blueblood hung his head fearing the lecture he would get the next day as the guests all calmly left his mansion.
At the castle, after a brief stop at Donut Joe's to get something to drink and a post party snack, the pair ran into Princess Luna as she returned from Ponyville. She grabbed the cup that Princess Celestia ordered for her as well as some doughnuts.
"So how was the party you went to?" The Lunar Diarch asked.