Umbral Rage

You embrace the void and allow it into your soul making you a being of pure rage and power, While the spell is active you gain these benefits 

• You gain 30 temporary hit points. If any of these remain when the spell ends, they are lost.
• You have advantage on attack rolls that you make with simple and martial weapons.
• When you hit a target with a weapon attack, that target takes an extra 3d12 necrotic damage.
• Any necrotic damage you deal while the spell is active you regain half of it as hit points.
• You have proficiency with all armour, shields, simple weapons, and martial weapons.
• You have proficiency in Strength and Constitution saving throws.
• While in this state if you are damaged on initiative count one you must make a Wisdom Saving throw the dc being equal to half the damage you took that turn. if you fail the saving throw you must use you reaction to attack the Closest creature to you 
• You can attack twice, instead of once, when you take the Attack action on your turn. You ignore this benefit if you already have a feature, like Extra Attack, that gives you extra attacks.

Immediately after the spell ends, you must succeed on a DC 15 Constitution saving throw or suffer one level of exhaustion.