Berserker Surge

You draw strength from recent bloodshed. If a creature within 30 feet of you has taken damage this round, you may tap into their suffering. Until the spell ends, your melee weapon attacks deal an extra 2d4 necrotic damage, and you regain 10 hit-points the first time you reduce a creature to 0 HP each round.

If no creature is harmed for a full round or your concentration is broken, the spell ends prematurely and you take 2d6 necrotic damage.