Eclipse is one of three legendary Demon weapons and has a counterpart, Transcendence.
In the game, Eclipse is an upper armor accessory. It can be obtained by defeating Duel in Thunder Hammer with greater chances in Champion Mode. Players may use Eclipse to forge Eclipse and Transcendence. Because Eclipse is always an Epic-type item, it is extremely hard to obtain.
Background
Eclipse is a weapon used by the demon Duel. It is said that Duel personally crafted Eclipse and wielded it in the Demonic Wars. Oz Pone Max Reinhardt created the Grandark to counteract the Eclipse. Though it is never actually seen being used, the fact that only Grandark can rival it suggests that Eclipse is a very powerful weapon.
Story

Thunder Hammer
As Zero caught up to Duel in Thunder Hammer, who was about to leave with the Deity Orbs he stole from the Grand Chase, Grandark felt pleased to finally meet the wielder of Eclipse.
End of the World Eclipse
Zero became worried for the girls in the group that they encountered in the city of dwarves after learning about the tale of a maiden's sacrifice in Aernas, but Grandark dismissed his concerns and pressed him to set his sights back on Eclipse.
In the sequel
Act 17.1: Traces of War in Forest
Alfred informed the Grand Chase that the Eternal Valley still bore traces of the ancient battle between Burning Canyon's head Werner and the Ancient Demon Duel due to the special power of Eclipse whose lingering energy had drawn monsters, making the forest inhospitable.
Act 17.5: Mysterious Device
Following the Grand Chase discovering the energy assembly devices the New Hardliners erected all over Burning Canyon, Jin speculated that the enemy might be extracting the special power left by Duel's Eclipse.
Act 19.9: Duel, Appears!
Zero proposed to distract Duel while the Grand Chase boarded the Underworld Train, reassuring everyone that he had Grandark by his side. He emphasized that defeating Duel's Eclipse with Grandark was the reason for his existence.
Item

"Forge relic items with the help of the immortal sword, Eclipse!"
- Level Requirement: 70
- Attack: 201
- Defense: 201
- Vitality: 0
Trivia
- In KOG Studios' official Naver blog, it was revealed that Grandark and Eclipse have humanoid forms. However, the purpose of these forms remains unknown.
- In EP 7: Acknowledgement of Zero's Likability, Grandark claimed that demon swords like him and Eclipse can feel each other's presence in resonance.
- In EP 8: Missed Match of Zero's Likability, it was revealed that Duel left behind Eclipse after the battle at the Tower of Memories and is currently in Oz's possession.
Gallery
References