Grimmcup

Grimmcup is the slash ship between Hiccup and Grimmel the Grisly from How to Train Your Dragon fandom.

Canon
When both Hiccup and Grimmel were young they had encounter a Night Fury that changed their lives. With Hiccup bringing humans and dragons together, while Grimmel makes it his mission to kill every last Night Fury. Grimmel had heard about Hiccup's dragon taming reputation, but because of his dark view on how to deal with dragons he didn't pay much attention to them or the dragon rider he views as a idiot boy.

How to Train Your Dragon: The Hidden World
After the Warlords inform Grimmel that Hiccup is harbouring the very last Night Fury, Grimmel grew a dislike to Hiccup and his idiotic vision for a human-dragon utopia world, as it gets him to expects the job of taking Toothless from Berk's young chief, while destroying his dream. Hiccup became aware of the seasonal Dragon Hunter when Eret recognised the tart Grimmel that is known for using in his hunting. Because of the villains that Hiccup has faced in the past he believes that he'll be able to defeat Grimmel with easy, but Eret warns him that Grimmel is a very dangerous man who likes to play games in his hunts. While Hiccup was looking through his late father's notes on the Hidden World, Grimmel had sneaked into Hiccup's house and sat on Stoick's chair to anger the young chief. Once Hiccup became aware of Grimmel's presence the dragon hunter demands Hiccup to hand Toothless over to him, but he refuses to. As Grimmel threatens Hiccup with his warning of what he'll do if he doesn't get want he wants, he tells Hiccup his story and how it made him the Night Fury killer before using Stoick's death and his owner point of view to taunt Hiccup. Once Grimmel noticed that Hiccup and his friends had set a trap for him and becomes enraged that Hiccup is still refusing to give into his demands, Grimmel gets his Deathgrippers to attack Berk. Seeing the damaged done to his home and tribe, Hiccup realize that Grimmel is indeed his greatest threat.

Not wanting to give Grimmel or the Warlords what they want, Hiccup decides to get his tribe to leave Berk in order for them to start anew within the Hidden World. On their way to the uncharted location, Grimmel uses his knowledge on Night Furies to help him get a general idea where Hiccup has fled to. Even though his people are far away from Grimmel's wrath, the thought of him out there looking for them made Hiccup worry and decided to plan an attack on him before he does one on them. As Hiccup and his friends went to capture Grimmel, they learn too late that Grimmel was expecting them and had set a trap. Hiccup is disgusted that Grimmel had drugged his dragons in obedience with their own venom. Despite them being able to escape Grimmel's grasps, he was able to find Hiccup's location through Ruffnut.

When Grimmel captured Toothless and took both him and all of their dragons away, Hiccup left that Grimmel had won and was powerless to stop him, until Astrid convinces him to not give up. Seeing Hiccup freeing his dragon, Grimmel decides to fight Hiccup in the air with a drugged Light Fury, knowing that it will get both Hiccup and Toothless to follow him. After Hiccup defeated the last of Grimmel's six Deathgrippers, he went straight for him but when Hiccup tackled Grimmel off the Light Fury, the dragon hunter had darted Toothless. As Hiccup watches the Light Fury save Toothless, while free falling, Grimmel attacks Hiccup and destroys his flight suit for ruining everything, and to ensure that he doesn't survive the fall. Luckley, Hiccup was saved by the Light Fury while Grimmel was left for dead.

Even though Grimmel is defeat and is believed to have died when he hit the water, the thought of him and his words got Hiccup to realize that Grimmel was right about the world of man not being ready to expect dragons. So he decides to send their dragons to the Hidden World without them, so people like Grimmel and the Warlords wouldn't harm them again.

Fanon
Fans find it ironic that Grimmel had a similar original story to Hiccup and how Hiccup might had gone down the same path as Grimmel if he had killed Toothless.

A popular dark AU of the ship have Grimmel using Deathgripper venom to control Hiccup like he does with his dragons, this original dark AU idea of the How to Train Your Dragon fandom is known as Venomcup. As Grimmel drugs Hiccup into becoming his human weapon.

On AO3 the there are only three fanfics on the two together, just as FanFiction.Net has two. The ship also has a very small fanbase on Tumblr and DeviantArt.

Fandom
FAN FICTION
 * Hiccup/Grimmel tag on FanFiction.Net
 * Hiccup/Grimmel tag on FanFiction.Net
 * Hiccup/Grimmel tag on FanFiction.Net

WIKI

Trivia

 * In the original HTTYD books, Hiccup's book counterpart has an ancestor called Grimbeard the Ghastly.
 * Like with Drago and two other villains from the TV series, Hiccup wasn't able to change Grimmel's mind about dragons.