Mantle of the Underworld

The Mantle of the Underworld is an ancient suit of black living-stone armor bought and restored by Sunny. Its five original enchantments provide broad protection, self-repair, variable weight, charm enhancement, and gradual growth through victories. After completing that growth, Sunny binds the relic to his soul; the Spell destroys the separate Memory but preserves and expands its powers as the Marble Shell Attribute, later known as the Onyx Shell and Onyx Mantle. (Chapters 310, 376–377, 493, 722, 1584, 2579–2651)

History

A broken relic restored

Sunny acquired the unidentified, broken suit from Stev for a handful of soul shards. Its fragmented name and damaged weave hid its true nature until Sunny became an Awakened and could circulate shadow essence through it. The armor changed from inert stone to stonelike metal, allowing its ordinary Memory restoration to repair the torn weave. Only then did the runes reveal an Ascended, sixth-tier armor called the Mantle of the Underworld. (Chapters 376–377)

The restored relic was jet-black plate made from living stone, intricately fitted into a nearly seamless barrier. Its description concerned a prideful demon who withdrew beneath the mountains after shedding divine blood. Sunny connected that language, the armor's construction, and its shared enchantments to Nether and the stone beings represented by Saint, although the Memory's precise succession before the First Lord's cohort remains unrevealed. (Chapters 377–378)

Armor that learned from victory

The Mantle became central to Sunny's Awakened combat style. It could withstand physical and elemental punishment, mend damage while supplied with essence, change its mass from feather-light to roughly that of a small mountain, and strengthen a slotted charm. Its durability never made Sunny invulnerable: impacts still injured the body beneath it, stronger attacks could penetrate it, and active repair and weight changes consumed essence. (Chapters 378, 440–443, 487–493, and 722)

Prince of the Underworld counted defeated opponents rather than kills, so Dreamscape victories and enemies left alive could advance it. The Mantle's effects gradually improved and their essence cost diminished as the counter rose. When Sunny finally accumulated six thousand victories, it advanced from the sixth to the seventh tier and gained Soulbound Relic, offering him the unexplained choice to bind it permanently. (Chapters 391 and 972)

From Memory to Marble Shell

Sunny accepted the binding during the Antarctic campaign. The Spell announced that the Memory had been destroyed, removed it from his inventory, and added Marble Shell to his Attributes. The new form retained Living Stone, Feather of Truth, Stalwart, and Underworld Armament, while adding mutually exclusive Shell and Mantle states and becoming a bound part of Sunny's body rather than a summonable possession. (Chapters 974–975)

As a dormant Shell, the Attribute reinforced Sunny's skin continuously but offered weaker protection and could mend only his skin, not internal injuries. As an active Mantle, it formed full armor without a summoning cost. Because both were part of his body, Sunny could augment them with his shadows and layer a separate armor Memory over the Shell. Its mind and soul resistance also rose from moderate to high after binding. (Chapters 975–976)

The Attribute later evolved with Sunny and was called the Onyx Shell or Onyx Mantle, manifesting across all seven avatars after his Transcendence. Subsequent Jade Mantle references concern a later evolution of this soulbound Attribute, not the continued existence of the original Ascended Memory. The original item therefore survives only as the foundation of Sunny's personal armor power. (Chapters 1584, 1907, 2238, and 2612)

Abilities and properties

Living Stone

Living Stone allows the worn armor to repair itself by consuming essence. It can restore cracks, gaps, and even damage caused by extreme heat, but the rate and extent of repair depend on available essence and augmentation. Before binding, the armor cannot function without the active flow that changes it from inert stone; afterward, the Shell version mends damaged skin but not the rest of Sunny's body. (Chapters 377–378, 440–443, 722, and 975–976)

Feather of Truth

Feather of Truth changes the armor's weight at will. Sunny uses lightness for speed and mobility and great mass to anchor himself or magnify impacts. At its demonstrated extreme, the Mantle weighs about as much as a small mountain, but the enchantment still cannot force a stronger captor to release him, negate momentum, or protect the body beneath the armor from transmitted force. It also consumes essence while active. (Chapters 378, 407, 487, and 493)

Stalwart

Stalwart originally grants extremely high resistance to physical attacks, high resistance to elemental attacks, and moderate resistance to mind and soul damage. That protection can delay heat, weapons, and hostile auras, but sufficiently powerful attacks still damage the armor and its wearer. When the relic becomes Marble Shell, its mind and soul protection rises to high while its passive Shell form remains weaker than the manifested Mantle. (Chapters 377–378, 440–443, 489–490, and 975–976)

Underworld Armament

Underworld Armament accommodates one charm Memory and both inherits and enhances that charm's enchantments. Sunny uses it to integrate effects such as Broken Oath's soul-eroding aura and Blood Blossom's reinforcement. The power does not create a charm or make its effect safe: hostile inherited auras can still harm Sunny, and only one compatible charm can occupy the armor at a time. (Chapters 376–378 and 487–489)

Prince of the Underworld and Soulbound Relic

Prince of the Underworld strengthens the Mantle according to victories. Its counter recognizes defeat without requiring death, and reaching six thousand raises the armor to the seventh tier and unlocks Soulbound Relic. Binding is transformative rather than reversible inventory storage: it destroys the separate Memory and turns its powers into a bodily Attribute with passive and active forms. The corpus does not establish a method for separating the relic again. (Chapters 391 and 972–976)

Ownership and custody