Fairemere Blade (5e Equipment)
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Weapon (longsword), legendary (requires attunement by killing a humanoid with the blade on you)
A blade containing the humanoid souls that it has slain. Before attunement, the blade acts as a normal longsword. In order to use the true power and be bonded to this weapon, you must use it to take the life of a humanoid, trapping it's soul within the steel. This is the equivalent of attunement. You have a +1 bonus to attack and damage rolls with this magic weapon. Once attuned to, you gain disadvantage with all other weapons apart from Fairemere.
Eternal Prison Whenever you strike the killing blow on a sentient humanoid, their soul is imprisoned within the blade. As long as a single soul is imprisoned in this fashion, the weapon deals an additional 1d6 necrotic damage.
Soulbond The Fairemere Blade draws strength from the wielder. When your reach 11th level and again at 15th level, this blade's bonuses to attack and damage rolls increase by 1.
Soul Shroud As an action you can summon any number of souls in sets of 2 that were stored in the blade for 1 minute. Each set of souls will work to protect you, whenever you would take damage, one soul set will intercede and reduce the damage you take by 2d6. Doing so causes the souls involved to cease to exist, any unused soul sets are released from the blades Soul Trap. You regain use of this effect after you finish a long rest.
Power of the Soul As Fairemere must feast on souls to gain power, if a day passes without it taking the souls of a humanoid, it deals xd6 damage to the wielder, where x is the number of the days passed without consuming a humanoid soul.
Cursed. The only way to put the souls trapped inside Fairemere to be put to rest and end attunement, is if the holder slays themselves with the blade. Only then, can the souls be released and put to rest in whatever higher plane they believe in. Once this happens, Fairemere soul count resets to 0 and returns to being a seemingly normal longsword, as it waits to be picked up by its next slave.