Balor's Blighted Eye

This ominous orb, resembling a cracked milky eye, glows with a sickly golden light. When attuned, you gain the following benefits: 1) Blight Vision: You can see in magical and nonmagical darkness up to 120 feet away. 2) Malediction: Once per long rest, as an action, you can target a creature within 60 feet. They must make a Wisdom saving throw (DC 16) or be frightened until the end of your next turn, as your eye's malevolent gaze overwhelms their mind. 3) Life Drain: If you reduce a creature to 0 hit points, you regain hit points equal to half the damage dealt. 4) Eye of Conquest: When you use the Attack action, you can choose to have a single attack gain an extra 1d10 necrotic damage. You can use this feature a number of times equal to your proficiency bonus; you regain all expended uses after a long rest.