Sanguine Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Kicker—Tap an untapped Vampire you control. (You may tap a Vampire you control in addition to any other costs as you cast this spell.) Target opponent loses half their life, rounded up. If this spell was kicked, you gain life equal to the life lost this way.