Blood Magic

You have learned how to tap into your own life force to fuel your spells.

You can cast spells of 5th level or lower without expending a spell slot. Immediately after you cast such a spell, roll 1d10, plus an additional 1d10 per level of spell slot used - reduce your hit points by the amount you roll. If you drop to 0 hit points as a result of this reduction, you cannot cast a spell in this way until you finish a long rest.

Spells that restore hit points that are cast in this way are severely weakened - instead of rolling dice to determine the amount of hit points a creature regains, the creature instead regains the minimum possible amount of hit points.