Blood Shield

You hastily carve into your body, drawing blood and using it to conjure a powerful shield fueled by your own vitality.

When you are about to be attacked by a creature within 5 feet of you, but before you know if the attack hits or not, you can choose to cast Blood Shield as a reaction. When casting Blood Shield the caster must choose a number of hit points they want to sacrifice (Max. 10) to create the Blood Shield. If the caster is hit by the attack, the Blood Shield takes the damage instead, if the Blood Shield survives the first, single hit of Damage after it has been fully calculated, the Blood Shield will explode dealing Force damage equal to the number of hit points sacrificed to cast it to the attacker, while also stunning them until the end of their current turn and healing you for half the damage dealt (rounded down). (This interrupts any other instance of damage they would have dealt after the first initial hit) If the Blood Shield is destroyed due to the first, single hit of Damage, or the attack misses, the Blood Shield vanishes immediately and if the Blood Shield was destroyed, the caster takes the damage they would have taken before the blood shield was made. You cannot sacrifice more Hit Points than you have available, you cannot use any temporary hit points to cast this spell.

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, the caster can sacrifice 5 additional hit points for each spell slot above 2nd.