Crimson Apotheosis

You enter a heightened sanguine state, turning pain into spellpower. For the duration, you gain the following benefits:

When you cast a Sorcerer spell that deals damage, you can deal additional Necrotic damage to one damaged creature equal to your Charisma modifier.
Whenever you take damage, you can use your Reaction to gain temporary hit points equal to your Charisma modifier + the spell’s level.
You have advantage on Constitution saving throws to maintain Concentration.

When the spell ends, you take 2d8 Necrotic damage for each round after the first that the spell was active. This damage can’t be reduced in any way.