School of Sacrifice

You learn to infuse the vitality inherent in creatures in your spells to enhance and modify them.

Blood Transference

You may use an action to drain the vitality of one creature of your choice within 30 ft. of you, your target makes a constitution save against your spell save DC or takes 1d8 necrotic damage and you gain 1d6 HP. This can be used this way a number of times equal to your proficiency bonus.

Alternatively you may give your life to others. As an action you may take 1d8 necrotic damage while an ally within 30 ft. of you gains 1d6 HP. This can be used this way any number of times.

Sacrificial Victim

When a creature dies from a spell you cast you may use your reaction to cast that spell again, originating from the creatures position, cast with your stats, and costing no HP from you. This can be used a number of times equal to your proficiency bonus. Alternatively, another creature may pay the cost for your spells, a willing creature may pay 10 HP/spell slot/spell level, and no augmentation or seeking can be used.