Bloodline - Transfusion

You sacrifice some of your health to mend another creatures injuries. You spend 1 hit die and take necrotic damage equal to the number rolled, and one creature that you touch regains a number of hit points equal to half of the necrotic damage you take + the number of hit dice spent (rounded up).

At Higher Levels. The amount of hit dice you can spend increases by 1 when you reach 5th level, 11th level, 17th level.