Starting at 14th level, you have served your patron well and now they grant you a new exchange. A piece of your life force in exchange for more power. As a bonus action you can make an offering to your patron. Doing so causes you to take 2d8 necrotic damage which can not be resisted in any way and the cost of your next offering increases to 4d8. The cost increases for each offering by double the dice and resets back to 2d8 upon completing a long rest. For your offering you are granted one of the following blessings:
Fortune: You roll three times and choose which result for your next ability check or saving throw. If you would have advantage you instead roll four times, whereas if you have disadvantage you roll two times.
Strength: The next time you cast a Warlock spell of 5th level or lower that deals damage, you don’t roll damage for the spell and instead deal the maximum possible amount of damage.
Youth: You regain one used Warlock spell slot.
If the damage from your offering reduces you to 0 hit points, you die.