|This article contains canon information corresponding to the Tales of Arcadia franchise. That means all information in this article is true and has appeared/been validated officially on-screen.|
The Sword of Eclipse, also known as the Eclipse Blade, is a new weapon wielded by the Trollhunter, which is created by the power of the three Triumbric Stones when they are inserted into the Amulet of Daylight.
When the Trollhunter incants "For the doom of Gunmar, Eclipse is mine to command!", the sword appears in his hand.
Such as its counterpart, it is made of light, but in this instance, it is more likely to be moonlight. It appears with the Eclipse Armor when the Amulet of Daylight is activated by the user and recognizes the Trollhunter in the process. With the power of the Triumbric Stones, the sword is the only weapon that is capable of killing Gunmar, as well as other Gumm-Gumms and trolls. Like it's counterpart, it can cut through most anything other that other troll-weapons.
However, it appears that it and possibly the Trollhunter's other weaponry are unable to kill wizards like Morgana since they are likely meant to only hunt trolls. Moreover, Morgana was able to destroy the sword, though Merlin was able to repair it without issue.