My infiltration into the Berkian world, years of building trust, behaving as if I were some buffoonish fop, kissing the boots of Stoick the Vast and his scrawny heir to the throne, all in pursuit of the one thing I could not obtain myself: The King of Dragons.[src]
— Johann revealing his true intentions
Johann was a seafaring trader who visits Berk from time to time, offering goods to barter for. However, he was later revealed to be allied with the Dragon Hunters, having secretly been working against the Dragon Riders by pretending to be their ally for years. He made his first appearance in the Dragons: Riders of Berk episode "Dragon Flower". He is the main antagonist of Dragons: Race to the Edge.
Johann has dark brown hair and beard tied into a twist knot. He wears an off-white sack hat on his head, long-sleeved shirt with deep blue white-swirled imprinted tunic and deep red sari over it, light gray cloth bracers on his arms (each bit of cloth goes between the second and third finger), brown belt with a yellow pack and knife around his waist, multi-colored pinstriped pants, and light brown boots. He also has a long scar under his left eye.
Obviously, this is why there are leaders and followers.[src]
Johann pretended to be a likable fellow, and everyone on Berk greatly anticipated his visits. His bargains seemed reasonable, and he even gave away an object freely from time to time. Stoick and Gobber seemed to enjoy his company and are quite willing to mend his boat when it is damaged. He does not dress in a typical Viking garb, and he talks in an English accent. Even though his garb is not typical of a Viking, he does still sail a typical Viking ship. His nationality is unknown, but he does claim Berk to be his favorite island (though he also says that Outcast Island is his favorite Island while he, Stoick, Gobber and the riders were there, but it might have been part of the plan or a marketing tactic.) He is certainly cultured from his many voyages, and because of this, he is greatly looked up to by some of the inhabitants of Berk and Outcast Island.
Johann may possess fighting prowess, as he claimed to have wrestled a giant squid for its ink, and was willing to act violently toward Snotlout, Ruffnut and Tuffnut for leaving him stranded in the middle of the ocean. However, despite his apparent friendly relations with Berk, he is still a businessman first, as he sold metal from a Berserker to Gobber, despite the fact the two have bad relations, implying he didn't care enough to warn them and when told it had led to all their metal being stolen as eggs were laid in the metal, he simply apologizes and says nothing can be done.
However, after the Dragon Flyers manage to obtain Heather's Dragon Eye Lens, it is revealed that his whole kind and easily frightened personality is fake and that he is actually evil and manipulative. The dragon riders find out about his deceit shortly after and are shocked to know that. He has secretly been after the "King of Dragons", and only begrudgingly pretended to be kind to Stoick and Berk to get close to them. In a way, Johann served as a distraction to get the dragon riders away from their island in several instances such as in: "Dire Straits", "Dawn of Destruction", "Edge of Disaster, Part 1", and "Edge of Disaster, Part 2". Johann is also extremely patient, willing to wait for many years in order to completely gain Stoick and Berk's trust (though Snotlout has doubted him several times already). The way he acted violently towards Snotlout, Ruffnut and Tuffnut hinted at his true nature.
— Hiccup to Johann when he showed him a secret passage to the Sandbuster's underground hideout
Though many saw him as a kind-hearted simpleton, he was actually incredibly devious, as he uses his intelligence to find a path to victory.
Intelligence: Johann is an extremely clever individual and has been revealed to be a master of deception, who battles with his intellect and his skills in combat. He is revealed to be behind nearly everything that has happened to the Riders since "Breakneck Bog" and he even managed to outwit Hiccup and the Riders numerous times - though he was never able to have them killed. He is extremely patient as he waited many years in order to completely gain Stoick and Berk's trust. His intellect has helped him outsmart the most intellectual minds like Viggo, who thought Johann would be easy to fool when he betrayed him.
Deception: Johann was a cunning master of deceit. He was able to manipulate every member of the Hooligan Tribe that he was an ordinary merchant so that he would understand their strengths and weaknesses. Johann was extremely patient and waited for years to gain the Hooligans' complete trust until the time was right for him to strike. He would often charm them with stories that he either made up or plundered from real merchants that he assassinated. Johann could tell if Viggo was betraying him through his time with the Vikings of the Archipelago.
Combat: Johann was exceptionally deadly in combat, and his primary weapons were his daggers that he had hidden beneath his sleeves. He was a capable marksman as shown when he threw his daggers with near pin-point accuracy and when he shot down the Skrill with a single crossbow bolt that was laced with Dragon Root. Johann was also rather proficient in physical combat, able to punch and pin down Hiccup for a certain amount of time. He had numerous real merchants plundered and assassinated after taking the tales of their travels.
It is revealed in "In Plain Sight" that Johann had been deliberately attempting to rid the Archipelago of the Dragon Riders since "Breakneck Bog".
The way Johann hid his daggers was probably inspired by the Assassin Brotherhood from the Assassin's Creed franchise.
Johann's method of plundering actual merchants' stories after killing them is similar to how Gilderoy Lockhart from the Harry Potter franchise stole other wizards' accomplishments after he obliviated (wiped out) their memories.
Johann's name, occupation, and character design seem to be an explicit reference to Trader Jones from cult British TV show Charlie Chalk. It must be said, however, that Jones lacked Johann's predisposition towards hurling sharp objects at teenagers.
Johann is arguably one of the Dragon Riders' most dangerous enemies, due to his immense cruelty to have any dragon or Viking killed to achieve his goal in capturing the Bewilderbeast in order to become the richest man on earth. Johann is seen as one of the smartest and most dangerous foes that Hiccup and the Riders have ever faced, having manipulated and outsmarted Hiccup and the Riders and nearly all the Vikings in the Archipelago since before the start of the franchise.
Though Johann has (very) many hidden daggers in his sleeves, everyone (including Johann himself) is completely oblivious to the dagger on his belt.
In fact, in "Breakneck Bog" he tries to "threaten" Hiccup he has a knife in his boot, then says he doesn't, regardless to the fact that he has one on his belt.