Auraphage

During the War for Terra, an age where the gods vied for dominion over the mortal realm, a fierce and violent battle raged for centuries in the depths of the Earth.  Qor, God of the Dead, and his twin sister, Termina, Goddess of Death, struggled for ownership of mortal souls lost in the Divine Conflict.  During the battle, Termina struck Qor's right arm, severing it at the elbow.  Though wounded, Qor managed to banish his sister to Necropoli, the realm of the dead.  Qor then fled the caverns, abandoning the arm in his haste.  The arm now rests at the bottom of Emeraude Cave, waiting for one of Qor's faithful to find.

Born of the lost arm, this fabled sword is said to be imbued with a modicum of the Corpse King's power.  The outstretched hand serves as its crossguard, sinew holds the radius and ulna together to form the handle, and a jaundice, bloodshot eye serves as its pommel.  At first glance, it appears to be an ordinary skeletal arm, but can be identified using an identify or detect magic spell, or by succeeding on a DC 15 Intelligence (Arcana) check.

You gain a +3 bonus to attack and damage rolls made with this magic weapon. 

As an action, you can speak this weapon's command word, causing dark green energy to sprout from the hilt in a wide, jagged blade.  The blade deals necrotic damage instead of slashing, and you regain hit points equal to half the damage dealt.  This weapon has the thrown property (range 20/60) and returns to your hand when thrown.

When this weapon reduces a target to 0 hit points, you gain a +1 bonus to damage rolls until the next short or long rest.

Random Properties. The Auraphage has the following random properties:

• 1 minor beneficial property
• 1 major beneficial property
• 1 minor detrimental property
• 1 major detrimental property

Cursed. This weapon is cursed, and attuning to it extends the curse to you.  While cursed, you are unwilling to part with the weapon, and you have disadvantage on attack rolls made with weapons other than this one.  Only a Wish spell can remove the curse.

When the blade is activated, you take 1d10 necrotic damage.  This damage cannot be reduced in any way.  At the start of each of your turns while the blade is active, you take an additional 1d10 necrotic damage.

Proficiency with a Greatsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Melee Weapon Attacks, Damage: Necrotic, Ignore Weapon Property: Heavy, creature, Heavy, Two-Handed, Graze