- "Sword Stealers have a magnetic personality . . . literally! Vikings that get too close find their swords and shields stuck to the Sword Stealer's hide!
Sword Stealers are impossible to keep out of battle...it's the best way to get close to spare swords and shields and build up their armor!"
Sword Stealer eggs have large grey scales. There appears to be six triangular plates that are fused together and a lava-like red substance can be seen glowing from underneath it through the gaps. This feature is like that of a Thunderpede's egg.
Hatchling to Adult
Newly born Sword Stealers are completely yellow instead of a dark color, as it does not have any metal armor. Once they have accumulated enough armor, the Sword Stealer is a mostly black dragon with some gray and white details. It has two wings and two legs. The tip of its tail ends with a arrow-shaped triangle. This dragon is unique in that where the wing claws would be located, it instead has triangular spear-like tips like on the tail. The Sword Stealer's size is very large, possibly as large as a Boneknapper. it is also very similar to a Razorwhip as both have metal (or metal like, in the case of the Razorwhip) scales.
Titan winged Sword Stealers are yellow, close to gold in color while their wings, chest and mouth glows blue. Also, they have an arrow-shaped tail. Their wings have brown stripes along it too.
Its magnetic skin attracts metallic objects like swords and this probably acts as a defense as it coats itself with a strong armor of metal. This is similar to that of a Boneknapper collecting bones to shield its delicate body.
It is noticeable that in Rise of Berk different Sword Stealer individuals have different colors of fire, regular Sword Stealers covered in iron armor have orange fire, Titan Wing Sword Stealers who are covered in gold have blazing blue fire, battle version Sword Stealers from Drago Bludvist army have an extra layer of armor and have green fire, and lastly exotic Sword Stealers have a more lightly colored unidentified type of metal and their fire is purple.
- The Sword Stealer bears a strong resemblance to the armored Boneknapper concept art.
- In Rise of Berk, the battle Sword Stealer has a green glowing mouth instead of an orange one. The reason for this is unknown, it may simply have more copper or other green burning chemicals in its fire or simply could be used for telling them apart.
- The Razorwhip may be based off this dragon, considering it has a metallic-like skin and the Sword Stealer attracts metal to its skin.