Johann's daggers look identical to any daggers or knives seen so far. Johann seems to be keeping plenty of them under his clothes, as he was seen throwing eight daggers during the fight in the lair of the Wild Sandbuster.
While Krogan and Viggo are arguing over how to obtain the Dragon Eye lenses in "In Plain Sight", Johann stopped them by throwing two of his daggers between them, which stuck on the Dragon Eye projection. He then throws another dagger between the other two when he agrees with Viggo in taking the lenses that are currently possessed by Hiccup.
After finding all the gems Hiccup needed to complete the Dragon Eye II, Johann takes one of his daggers from under his clothes and demands the lenses Hiccup was carrying. Giving him another bag instead, Johann takes out two daggers and throws them in a mirror with Hiccup's reflection. He then throws multiple daggers at Hiccup, with the latter dodging all of them with Inferno. When Toothless blasts one of them, the Wild Sandbuster appears. Hiccup and Toothless manage to chase it away while Johann makes his escape.
When Viggo attempts to fool Johann and Krogan in "Triple Cross", Johann can see through Viggo's deception and corners him to a wall with one of his daggers. Viggo, however, fights back when he releases and detonates Hideous Zippleback gas from his fire sword.
In "King of Dragons, Part 2", Hiccup confronts Johann and Krogan in the Berserker Bewilderbeast's lair. Johann manages to knock down Hiccup and takes out a dagger to kill him. Hiccup moves his head in time and the dagger sticks in the ice.
- The way Johann takes out his daggers and throws them is very similar to how Hela does this in the film Thor: Ragnarok. It is also quite similar in how assassins from the Assassin's Creed franchise reveal their hidden blades.
- Johann might have made an allusion to his daggers in the episode "Breakneck Bog" when he said "I have a knife in my boot! I don't have a knife in my boot..."