The Ark Rouge (アークルージュ), also known as the Crimson Vessel (紅い聖櫃), was one of the Sept-Terrions and was the treasure governing Fire. In contrast to the Lost Zem, which has dominion over physical bodies, the Ark Rouge has dominion over souls.
It was originally situated in the land now known as Erebonia, and was worshipped by a civilization known as the Witches. After clashing with the Lost Zem in a cataclysmic battle that destroyed both treasures, they fused into the Great One. The Ark Rouge's lifeless body can be seen at Bryonia Island.
- The Ark Rouge's title, 紅い聖櫃, which translates more directly to the Sacred Red Ark, refers specifically to the Ark of the Covenant.