Antiquited Blade/Charon’s Fury

Weapon(Longsword), Legendary(Requires Attunement)

This ancient looking sword appears to have seen better days. A faint heat can be felt coming from the blade.

Dormant Stage

Upon finding this weapon, it appears to be a Longsword of an ancient design that has seen better days. A successful Intelligence(History) check with a DC of 15-25 based on DM decision will reveal the design to hail from a civilization that worshipped a Goddess of Flames that was known for their purifying aspect. A Detect Magic spell will reveal a very faint aura of Enchantment magic.

The first time a player takes a Long Rest after attuning to this sword they hear a faint voice in their head of a woman sounding like she recently was awoken from a long slumber.

“Hmmm, Oh, another one.”

This Longsword has a +1 bonus to Attack and Damage rolls. While holding this Sword, the player finds that they cannot use a shield or another weapon in their offhand.

The first time a player scores a critical hit using this weapon, the following events happen:

The foe takes an extra 2d6 fire damage

The player takes 1d4 fire damage

The player hears the Woman’s voice again, this time slightly louder and less sleepy. “Oh, that was good. Maybe you’ll do better than the last.”

From now one, the Weapon deals an additional 1d4 fire damage on hit. The DM can now begin a countdown. After dealing the killing blow on 20 monsters or getting 20 Critical Hit, whichever comes first, the Sword advances to its Awakened stage.

Awakened Stage

Upon moving to the Awakened Stage, the player once again hears the Female voice.

“You have done well, Mortal. I believe you are worthy of my Blessing.”

Upon accepting the blessing, the following events take place:

The sword gains an additional +1 bonus, bringing it to a +2 Weapon.

The Fire damage increases to 1d6

Scoring a Critical Hit activates Her Blessing for 1d4 rounds.

The Weapon becomes Cursed. While Cursed, the Player is suffers Disadvantage when making attacks with any weapon aside from this one. The Player is unable to unattune to this item unless a Remove Curse spell of 5th level or higher is cast.

The Sword will now respond to the Player when they address it, and when certain external stimuli are applied.

Her Blessing grants the following effects:

The fire damage increases to 3d8

The player suffers xd4 fire damage where X is equal to half your player level, rounded down

The player may make an additional attack each time the Attack Action is taken.

If the player decides to refuse the Blessing or if they break the curse, they hear the voice scream angrily, “You dare deny your Goddess!? You are a fool!”. Their attunement to the Sword is immediately broken and they must make a Wisdom Saving Throw with a DC equal to 10+Player Level, taking 4d10 Fire Damage on a fail and Half on a save.

Credit to Grinding Gear Games