Dark Vitality

You have resorted to forbidden magic to increase your life span, granting you the following benefits:

• Dark Magic. You learn the chill touch cantrip. Additionally, you learn the inflict wounds spell and can cast it once without expending a spell slot. You must finish a long rest before you cast it in this way again. Constitution is your spellcasting ability for these spells.
• Drain Life. When you deal necrotic damage with the spells you learned from this feat, you can regain hit points equal to half the necrotic damage dealt to one creature. You can use this ability a number of times equal to your proficiency bonus, and regain all expended uses when you finish a long rest.
• Unnatural Longevity: Whenever you deal necrotic damage from any source, your life span increases by a number of days equal to half the damage taken.