Derrax

Despair is a long sword made of Adamantium overcharged with Dark Mana. It was crafted by a Dwarf swordsmith but it wasn't able to be inscribed with runes or any enchantments because of how heavily the sword was cursed.

Indeed, the sword will incite fear, confusion, bleeding, corrosion and Mana chaos on those wounded by it. The Dark Mana will eat and tear the inside of all being: physical or incorporeal. It can also erase magic to an extent because of its blade being made of Adamantium, a legendary metal famous for its anti-magic properties. Finally, Despair will do everlasting damage to those that survive its blade, leaving their body and soul in agonizing pain until the wound is healed.

The sword is incredibly heavy, but Derrax is able to wield it normally because of his Blessings and his Belt of Giant's strength. Its curses doesn't affect him for some reason; either because of his Blessings, the blade recognizing him as its master, his mental strength or all of the above.

The way the Adamantium became so corrupt is a mystery. Adamantium is a metal that reject magic, so for it to be cursed must have required extraordinary circonstances.

Despair is a very good sword that only a master swordsman will be able to wield to its full might. If it gather enough fame, it has the potential to become a legendary artefact, maybe even getting its own consciousness.

The first weapon that Derrax got in the world he got reincarnated into was a long sword which was called Sword of Average Darkness. Disliking the name, Derrax used its acronym(SAD) to name it [Sadness]. The sword helped him during his early months, saving his life and ending those of monsters with its nasty Darkness attribute enchantment many times.

The sword was broken beyond repair however, Derrax destroying it in a reckless attack against a strong monster. The strength of the man was too much for the sword to handle... Derrax used other weapons after the incident, never forgetting his first sword.

One day, Derrax, now Baron Derrax Wischard, after a monster extermination request in a cave found a black lump of metal. Deciding to take it with him, he later discovered that it was in fact Adamantium overcharged with Dark Mana. This was impossible, as Adamantium was well-known for its terrible magic conductivity. Derrax theorized that it was used a long time ago to seal a cursed item of some kind, though its whereabouts are now unknown.

While it could be sold to an interested mage, the young knight decided to use it to improve his equipement. He used most of his money to have a famous Dwarf swordsmith forge him a long sword. The result was incredible, the sword so sharp that it could cleave an armored man with a shield in two; if enough force was put into the blow of course. It was named Despair, as it would strike fear in the heart of its target.

After sadness came despair after all.