Undying Frenzy

You trigger a wild, beast-like frenzy in your soul, becoming brutal and unstoppable. You may take as many actions and reactions as you want until the start of your next turn. Additionally, you may move up to 10ft on any other combatant's turns until the start of your next turn. Taking an action or reaction now inflicts 30 necrotic damage to you and reduces your hit point maximum by 15. Using the 10ft of movement on someone else's turn also inflicts this damage effect.

You may only take actions on the turn you cast this spell on, but reactions and the 10ft bonus movement can be done on any subsequent turn until the start of your next turn. The 10ft of movement cannot be increased by any means. The hit point reduction cannot be recovered by any means.

All actions and reactions you take have advantage on any d20 rolls. You deal a bonus 1d6 necrotic damage per attack or spell attack. 

If the damage you take from this spell reduces you to 0hp, you may take one more action. If this final action is an attack or spell attack, and if it hits, it critically strikes. If you roll a natural 20 on this attack, it critically strikes and kills the target if the target would be left on less than 50 hit points. Once you have taken this final action, you are dead and can only be revived at the DM's discretion. 

The damage per action increases by 5 for every player level beyond level 9 (Totals are; 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85). The maximum hit point reduction remains at 15.The bonus damage per attack increases by 1d6 for every player level beyond level 9.