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 Holy Weapons (聖武器 Shiseibuki?) 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 bodies.
- 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.
- Wave Summon
- Upon wave spawn, the Legendary Heroes and their respective parties are transported to close proximity of the Waves of Calamity.
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.
- Absorption: Weapons can absorb loot such as items and materials to unlock new variations of the Legendary Weapon and may equip said variation if they meet its prerequisites.
- Weapon Transformation: Weapons can transform into different variations that grant new equip bonuses including stats, skills, and abilities. Additionally, with enough experience or other prerequisites, 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.
- Mastery: Using the same weapon would improve your proficiency with it.
- Energy Transfer: when you finished using a weapon, you could reset its mastery level and release the amount of energy you had invested in it. Finally, any items that you had absorbed into the weapon could also be turned into energy.
- Increasing Rarity: by imbuing a weapon with energy, you can increase its rarity level. This tends to increase the weapon’s abilities.
- Smelting: You can power up a piece of equipment using ores. There is a chance of failure.
- Spirit Enchantment: Pieces of monsters' souls, or items, that have been absorbed into a weapon can be used to imbue the weapon with special powers. This has no chance of failure-maybe.
- Status Enchantment: stats can also be increased in the same way.
- Power Up: The power of a weapon can be raised by equipping it with certain ores. This never fails.
- Item Enchantment: Items that have been absorbed into a weapon can be turned into energy, and that can be used to raise the percentage of various stats. The success is based on probability, and therefore there is a chance of failure.
- Job Level: You can increase your stats by using the energy contained in absorbed monsters or items.
- Sharing: Share the power-up methods from other legendary weapons and vassal weapons.
- Trust: Trusting and being trusted leads to an increase in abilities.
- Energy Boost: The heroes have an energy that they draw out automatically as power from the weapons, and this is always active. Assigning this energy to skills will allow more powerful skills to be used.
- Power-Up Points: Points were acquired based on your current level, and they could then be spent on magic or skills.
- Enhanced Customization Via Money: you must spend money to enhance yourself. It only works when combined with other power-up methods. It also cancels out failure at refinement.
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.