The Legendary Weapons (伝説武器 Densetsu Buki?) are summoned and wielded by the Four Legendary Heroes from another world. They are also referred to as the Four Heavenly Weapons (聖武器 Seibuki?) since many religions formed centering around the Legendary Heroes.
The origins of the Legendary Weapons are still unknown. It is speculated that the Vassal Weapons have a deep tie with the Legendary Weapons and the origins of the world.
Their objective is to defeat the current set of Waves of Calamity, after which the users are allowed to resign back to their worlds.
Legendary Weapons are summoned in response to the waves, appearing in sets of unique weapons, usually four in total. The summoning ritual will also select people from other worlds to wield these weapons; in Naofumi's case, he encountered The Record of the Four Holy Weapons while browsing the library. Once a Legendary Hero is deceased, their weapon will disappear in wait to be summoned again with a new hero. The weapons can be resummoned if either the current set of waves is vanquished, or the set of weapons is expunged. With each weapon missing, the waves are said to grow stronger.
Legendary Weapons specialize in protecting the world they reside in. They upgrade through adventuring within their respective worlds, with each world having different power metrics.
- See also Vassal Weapons
Legendary Weapon potential is superior to Vassal Weapons, but have more restrictive functions.
All weapons possess a gem that acts as the functional matrix to activate abilities, this gem persists through transformations.
- No level cap and no class-up requirement.
- Immunity to slave seals and other control type curses.
- Possessors of the Legendary Weapons are unable to gain experience when in close proximity of each other.
- Possessors may not equip weapons that are not of the same class as the Legendary Weapon itself. Additionally, possessors cannot remove the Legendary Weapon from their body.
- Verbal language is translated to the user in their primary language while the user’s primary language is heard by the recipient in their primary language.
- Weapons can absorb loot such as items and materials to unlock new variations of the Legendary Weapon and may equip said variation upon meeting specified conditions.
- Weapon Transformation
- Weapons can transform into different variations that grant the user new equip bonuses including stats, skills, and abilities. Additionally, with enough experience or other conditions being met, the user may permanently retain the equip bonuses even if they switch transformations. (Some bonuses remain exclusive.)
- Weapon Copy
- The user can copy weapons of a similar class to the Legendary Weapon that they encounter and store them for later access. Equip bonuses may still require materials to unlock, however.
- Strengthening Method
- Weapons have various strengthening methods that are selectively revealed to the user's interface upon assignment. Other users can enable these systems only if they genuinely believe they exist.
- Learning from other users will provide bonuses to both and is not limited to any individual world.
- Wave Summon
- The Legendary Heroes and their respective parties are transported to, or within close proximity of, Waves of Calamity. Upon clearing, neither the Heroes or their parties are teleported back to whence they came.
Legendary Weapons respond to the user's strong negative emotions caused by heavy emotional or physical strain and traumatic events, unlocking the Curse Series variant related to said emotions.
The Curse Series grant powerful effects, stats bonuses, and abilities, but a severe penalty which scales to the severity of the curse level is applied to the user when the variant is removed or its skills are used.