Blood Moon

This weapon appears as a black haft, about one-and-a-half feet long and made from a single crystal of sable onyx. Raised runes are carved up and down the haft, providing grip. The weapon contains a sliver of the light of Hadar, a faint red moon under the influence of the Far Realms that orbits high above the material plane.

While you are wielding the weapon, you can use a bonus action to cause two trembling blades of red light to spring into existence, one from either end of the weapon. You can also use a bonus action to dismiss the blades. While active, the weapon sheds dim red light within 10 feet. In this area, bright light is reduced to dim light.

Dormant

• You gain a +1 bonus to attack and damage rolls with this magic weapon, which deals necrotic damage instead of slashing damage. Attacks with this weapon ignore the Shield spell.
• When you hit a creature with the weapon, they cannot regain hit points until the start of your next turn.
• Once per long rest while the blades are active, you can lash out with the weapon in a whirlwind attack around you, casting Arms of Hadar at a level equal to your proficiency bonus.

Awakened

• The weapon's bonus to attack and damage rolls increases to +2.
• If you reduce a creature to 0 hit points with an attack from the weapon, you gain temporary hit points equal to your level.
• Once per long rest while the blades are active, you can cast Hunger of Hadar, draining the light from that area into the weapon. You can see through the darkness created by the spell.

Exalted

• The weapon's bonus to attack and damage rolls increases to +3, and it gains the Reach property.
• While the blades are active, you can use your reaction when you are hit with a ranged attack to deflect it. Make an attack roll with this weapon against a target within 30 feet of you. If it hits, that target is hit by the attack instead. This cannot be used against critical hits, and only a number of times equal to your proficiency bonus times per long rest.
• Once per long rest while the blades are active, you can cast Shadow of Moil, coating yourself in the light of the corrupted moon.