Toothless

Toothless is a Night Fury, the strongest and most intelligent of all dragons. He is Hiccup's companion and best friend, as well as his main protection and transportation.

Appearance
Toothless is black with purple tones. Unlike other dragons who are spiky and reptilian, toothless is sleek and feline. He has two gigantic black wings as well as two smaller wings behind them. His tail has two fins, one on each side that help him fly, though one is artificial. He has two gigantic eyes on the front of his face that are immensely expressive, being able to become slits like a hunting cat, or widen into saucers like a puppy.

Personality
Toothless is the most intelligent of all dragons. He seems to have a dry sense of humor matching his rider. Such instances include shrugging his shoulders at the threat of Astrid telling the village about him, and taking her on a roller coaster ride rather than depositing her safely on the ground like Hiccup wanted. Toothless understands human speech extremely well, immediately evening out his erratic flight when he hears Astrid apologize, and having a look of pleasure on his face when he sees she has come around to the dragons.

Powers and Abilities
As a dragon, Toothless has the power of flight and to breath fire. Being a Night Fury, he is the fastest dragon, able to  fly at almost supersonic speeds. With his dark coloring, he is invisible at night. His most powerfull ability is tofly high, and tuck his wings into a dive bomb, letting out a blast of extremely powerful fire that is strong enough to knock the Red Death off its feet. This dive bomb generates a shrieking sound, letting those unlucky enough to be its target when to take cover. Since losing one of his tail fins, he has had to rely on a special prosthetic created by Hiccup to fly, with Hiccup controlling it, which is how he prefers it. It may be that with Hiccup helping him, Toothless can fly better than he ever could on his own.

Weapons
Night Fury's are said to be amazing fighters. And Toothless is a night fury. He is one of the main protection for the group other than Jack 's ice and Merida 's arrows. Toothless has three main weapons - claws, teeth and fire breath.

Claws - Like other dragons, Toothless has claws that can help him climb when he can't fly, attack enemies etc.

Fire Breath - Night Fury's breath fire, but their fire tend to be purple mixed with a bluish-white colour.They use their incredible explosive fire to damage any unlucky foe. It is shown that a Night Fury can switch between diferrent fire styles; In the TV series Hiccup  tells Toothless to use "plasma blasts". Plasma blasts are purple fire-bolts that explode on target almost instantly. These are a Night Fury's primary defense and are very lethal. Second is the fire a Night Fury uses to warm up the place where it will sleep, as seen on the movie and the TV show. This fire isn't particularly strong, but it can light up fireplaces and stoves.

Teeth - As a Night Fury, Toothless has the ability to retract his teeth. This unique trait can make him appear to be toothless, hence his name.

Hiccup Horrendous Haddock III
Hiccup is Toothless's rider, companion, and best friend. Hiccup is the one who shot Toothless down and wounded him, although Toothless doesn't seem to be aware of the fact, or if he does, has forgiven him. Toothless values Hiccup above all others, protecting him from any perceived threat. Toothless isdependent upon Hiccup for flight, and seems to prefer this to any other alternative, as shown in the Gift of the Night Fury, where he smashes the fully functional automatic prosthetic that allowed him to fly on his own and had Hiccup use the old saddle, showing that he flies with Hiccup, not just carries him like other dragon's and riders.

Jack Frost
Jack and Toothless have little contact other than through Hiccup. The only thing the dragon and the winter spirit have in common is that both fly. Given Jack's mischevous and troublesome personality, Jack would take the longest (or at least the hardest) for Toothless to trust completely.

Merida DunBroch
Toothless shares a light bond with Merida through Hiccup, and the fact that Merida has an affinity for animals through her own horse. In fiction she is most commonly the one who rides Toothless behind Hiccup.

Rapunzel Corona
Toothless has interaction wtih Rapunzel but not much. The closest interaction they have would be Rapunzel offering to heal Toothless tail. With Rapunzel's open and innocent personality, it is likely for Toothless to trust Rapunzel quicker than Jack or Merida. Because of rapunzel's personality towards animals, Toothless does like a few scratches or pats from Rapunzel.

Pitch
Pitch and Toothless don't meet much but Toothless tends to attack and get very aggressive when Pitch preys on Hiccup's doubtful self. Toothless recognises Pitch as an enemy and as someone he has to attack as well as protect his master, Hiccup and his friends from. Unfortunately, Pitchs' ability to dissolve into shadows means that he can easily escape from Toothless's attacks.

Mor'du
Mor'du and Toothless are both very strong when it comes to combat. Mor'du finds Toothless a troublesome object that blocks him from his main 'prey' - Merida. Mor'du never backs down from combat with Toothless. Likewise Toothless attacks nevertheless under Hiccup 's command.

Mother Gothel
Toothless treats Gothel just the same way as he treats Pitch. He doesn't dail down his moves and would do anything to protect his master and his friends.

Red Death
After Toothless had defeated Red Death at Berk. Red Death had sworn Toothless and Hiccup as his rival and would do almost anything to get rid of them. Despite his pride and aggressiveness, he allowed Pitch to ride on him during battles because he knows that the nightmare sand Pitch creates can form powerful blasts with his dragon fire. Still, Toothless and Hiccup can bring a fight to Red Death. Toothless depends on his friends and does his best to defeat Red Death once again.

Physical Appearance and Personality
In the How to Train Your Dragon book series by Cressida Cowell, Toothless is a remarkably small, green Common or Garden dragon. He has innocent, grass green eyes and long eyelashes. Contrary to his sweet appearance, Toothless is a quite disobedient, selfish dragon who causes all sorts of trouble, from which Hiccup has to rescue him from.

Role in the Books
Hiccup captures Toothless in the very first book of the series (simply titled How to Train Your Dragon). From that book on, Toothless joined Hiccup in his misadventures- sometimes helping, sometimes causing problems.