Vassal Chain

The Vassal Chain is one of the supposed Vassal Weapons from S'yne's destroyed world. The current wielder is S'yne's Sister.

Overview
According to S'yne, her sister is a traitor who destroyed their own world. It seems that the Vassal Chain is a weapon from that destroyed world. Since then, S'yne's sister had been working for the organization behind the waves.

She was first seen by Naofumi and the other heroes while testing technology with Miyaji and made several other later appearances - showing off her incredible power each time. During the battle with the Harpoon Reincarnator's forces, Naofumi and the other heroes were successfully able to destroy the control accessory which prevents the Vassal Weapon from leaving unworthy wielders. However, unlike every other weapon which was controlled by this accessory, the Vassal Chain stayed with S'yne's Sister after the accessory broke.

Power-up Method
The power-up method for the Vassal Chain is unknown.

Trivia

 * Information to be added later on.