Relentless Assault (fixed)

When you hit a target who has already taken damage, you can add 1d4 extra damage of the same type of damage you inflict. The next time you hit the same target, deal 1d4 extra damage as previously described and your Relentless level is upgraded by 1 on that target, causing your Relentless die becomes one size bigger (d4 to d6, d6 to d8, etc.) up to a d12. When you roll a natural 20 on your attack roll for a target you can roll a Relentless die for, you do extra Relentless damage equal to three rolls of your current Relentless die, and if possible, upgrade your Relentless die by 2 levels on that target after inflicting damage.