Toothless is the most likely one. Their bond is so strong that Toothless would sense Hiccup's distress and come to his rescue. He could fly into Drago's hideout and cause chaos to free Hiccup.
In this kind of fanfiction, perhaps Hiccup would be in great danger. Drago might use Hiccup as a hostage to get something he wants, like controlling the dragons that are allied with Hiccup's people. He could also try to force Hiccup to reveal the secrets of his unique bond with Toothless.
His relationships with others can also be a big part of his character development. If he meets other captives or his kidnappers, how he interacts with them, whether he tries to understand their motives or just fights back blindly, can show his growth. Maybe he starts off being angry and vengeful but then realizes that there's more to the situation and becomes more empathetic.
One popular fanfiction with this plot might be 'Dragon's Captive'. In it, Hiccup's kidnapping by the dragon leads to an unexpected bond forming between them. The story delves into how Hiccup, using his unique understanding of dragons, tries to communicate with his captor.
Well, one plot development could be that Hiccup uses his wits to escape. He might study the dragon's behavior while captive and find a weakness to exploit. For example, if the dragon has a particular routine when it leaves the lair to hunt, Hiccup could use that time to make his escape.
One common plot twist could be that the kidnapper turns out to be someone Hiccup thought was a friend all along. This adds an element of betrayal and shock to the story.
It could be that a group of rogue dragons, wanting to teach humans a lesson, decided to take Hiccup hostage. Maybe they had a grudge against his dragon-training methods or were just looking for some sort of leverage against the humans.
It could go a few ways. Maybe the friends of Hiccup form a rescue team and come up with a strategic plan to find and free him. Or, there could be some unexpected twist where Hiccup manages to escape on his own with the help of a dragon. It all depends on the creativity of the author.
Well, when baby Hiccup is kidnapped in fanfiction, it often leads to a series of exciting events. Maybe the dragons play a crucial role in the rescue mission, or it brings out hidden strengths in the other characters. The plot can take many twists and turns.