TL;DR My players faced an Archfey and circumvented 2 weeks worth of work in the most badass way possible

I (the DM) was running a 5e homebrew campaign for some of my long time friends who were all new to DnD.

The party consisted of Carl (Level 11 Aasimar Druid), Robert (Level 10 Elven Eldritch Knight), Ben (Level 11 Gnome Evocation Wizard), and Winston (Level 9 Tiefling Warlock). They were all loving the game and being creative with their roleplay and having a lot of fun. We had homebrewed a lot of things in order to keep that "fun" factor because I try to be a chill DM and keep it fun yet fair. One of the things we homebrewed is giving the Warlock the "Divine Intervention" feature that Clerics have, but they call upon their patron instead. Because I figured that would be interesting and because it would make sense with Winston's backstory, I allowed it.

After 20 sessions, all of my player's had established their character's personalities and how they would play them. Carl was the talker and negotiator, Robert was the easy-going yet stoic tank, Winston was the edgy, in-the-shadows one and Ben was the horny comic relief, and the argumentative one. Ben's backstory was that he was a simple rabbit farmer, but his entire flock was taken by an Archfey, and he went out on an adventure to retrieve them. Along the way, he found an overturned carriage of books (thus how he became a Wizard).

After the party arrived in the main city for information, they had also found information about where Ben's rabbits may have ended up. The four of them split the party and Ben and Winston ended up going together to investigate a guild who seemed to worship an Archfey (while Robert and Carl went to investigate more of their own personal business). After some time they found the seeming headquarters of the guild. They busted their way in, navigated the labyrinthine corridors and found the entrance to the inner sanctum.

Because of Ben's talkative personality, he reveals that they were just looking for his rabbits. The guild had Ben's rabbits, causing him to grow angry at the guild and he threw a large fit. They inevitably get captured by the guild (voluntarily) and were escorted to an abandoned church with 100 magic-using guild members staring at this small, grinning Ben and a very disgruntled Winston. The leader of the guild, an angry hulking Minotaur, knocked out Winston and they locked him into a back room.

Ben: "I want to convince them that I want to join the guild"

Me: "Roll Persuasion"

B: "Nat 20"

The Minotaur begrudgingly agreed to his terms, seeing as his connection to the rabbits was a good enough reason to let him join. The process of indoctrination requires the guild to summon the Archfey herself. I designed this Archfey for around 2 weeks, trying to make her a complex villain and give Ben a good reason to hate her beyond taking his rabbits. Good thing all of that work will be thrown out the window right? sigh

As the summoning ritual takes place, Winston wakes up in the room and hears the commotion. He waits in the room apart from the chaos and just listens to try to intervene if anything goes wrong. Que the Archfey and Ben conversation. Being the horny gnome that he was, it didn't go very well.

Ben: "Gimme my rabbits back"

Archfey: "Never! They are my favorite delicacy, and if I have summoned that must mean that you are here to feed me and join my cause!"

B: "I would never join the Cult of the Broads, are you kidding?" (Referring to the simple fact that the Archfey was female, and literally no other reason)

The Archfey begins to force choke Ben, and the Archfey being not too happy with Ben's comment. Winston, after a very high perception roll, decides that now would be the best time to intervene. Keep in mind, he has no idea what is actually going on because he can't see Ben, he just knows that if Ben isn't talking, something is horribly wrong.

Winston: "I can't see him and I don't know what's going on, so I guess all I can do is try to see if my patron will help. I'm gonna try to use that Demonic Intervention"

Me: forgot that I had implemented that because it was over 20 sessions ago "Oh yeah... okay roll for it."

Winston: "Does a 5 (on the d100) work?"

My heart sank. The intervention worked, and so I asked him what he wanted to ask of his patron. His patron loved death and chaos, and so naturally Winston asked his patron to "Get rid of whatever was hurting his friend." After another very high persuasion roll, and his patron seeing this as an opportunity to dismantle an entire guild, gladly agreed. What followed was Ben dropping back to the ground, about two minutes of this Archfey being ripped to pieces by Winston's tentacled patron (WINSTON NOT BEING ABLE TO SEE ANY OF THIS), and every single guild member looking in horror upon their great deity being eviscerated in front of them.

Ben: yelling to the guild members "THAT'S WHAT HAPPENS WHEN YOU CROSS ME! NOW BOW BEFORE YOUR NEW LEADER!"

His persuasion roll: total of 21. My insight roll for the group: Natural 1. The guild members collectively pissed their pants, surrendered entire control over to Ben, and Winston taking none of the credit for it at all. After this chaos, my table was silent except for Ben's PC laughing hysterically, and me shuffling papers together and deleting two pages of notes from my laptop about the Archfey.

One of my favorite moments by far at the table, and definitely Ben's luckiest and most erratically funny moments of the entire campaign thus far. I'm glad my group is loving it and hopefully that continues until they finish. Ben and Winston will forever be the Mid-Leveled Duo to kill (basically) a God.