Vessels (神器 Jingi , lit. "God's Vessel" or "Sacred Treasures") are special items used by Flame Haze's contracted Crimson Lords to express their will and talk to other people while their bodies reside within contractors' body. Also, these Crimson Lords can telepathically converse with their contractors without speaking. These items are entirely different from Treasure Tools as they are unique to a certain Crimson Lord and can only be possessed by Flame Haze. If the Vessel is damaged or destroyed, it can be repaired or recreated since the Crimson Lord reside in the contractor's body, not the Vessel itself. The unique ability of Vessels is that they can teleport themselves back to wherever their contractors are. There are likely two types of Vessels: those that are used as decorations and those that are used as weapons.
- The name of the Vessel usually corresponds to the legend of the contracted Crimson Lord's earth name, but sometimes it relates to the contractor's place of origin before making a contract.
|Character related||Colored Silhouette • Crimson Denizen • Crimson Lord • Crimson God • Faux Vessel • Flame Haze • Kraken • Mystes • Rinne • Servant • Torch • Tuner • Unrestricted Spell Master|
|Conflicts||Ancient War • Sovereign's Game • Great War • Civil War • Révolution War • Second Great War • Chaotic Period|
|Events||Misago Festival • Seishū Festival|
|Items||Crystallization of Self-Research • Treasure Tool • Vessel|
|Creations||Divine Gate • Iron Giant • Statue of Pride|
|Metaphysics||Divine Summoning • Flame • Manifestation • Power of Existence • Rift Crossing • The Truth of This World • Unrestricted Spell|
|Organizations||Bal Masqué • Brothers of the Maccabee • Hyakki Yakō • Jewel Gang • Minack • Outlaw • Révolution • Töten Glocke|
|Phenomena||Distortion • Great Calamity • Faint Heaven Quake|
|World||Crimson Realm • Great Binding Chain • Maelstrom of Warfare • Rift Between Both Worlds • Xanadu|