Ward of the Bleeding Heart

You choose to protect a creature from harm, at the cost of your own safety. For the duration, you can choose one friendly creature within 10 ft. of you to protect. The target's armor class increases by a number of your choice, up to +10, but your own armor class is reduced by the same amount. (You cannot use this spell to lower your armor class to less than 5.) The effects last up to 1 minutes. If either of you move further than 10 ft. away from each other, the effect immediately ends for both of you. Each time you take damage while concentrating on this spell, you must make a DC 12 Wisdom saving throw. On a failed save, the sacrifice you are making takes its tole on you, and you become vulnerable to all damage types until the start of your next turn. This bypasses any resistances or immunities you have. All creatures around you will be able to tell you are weakened. If you incur vulnerability and the spell ends for any reason, you still have vulnerability until the start of your next turn.