Demonic Rage

In battle, you fight with a demonic intensity. On your turn, you can enter a Demon Rage as a bonus action.

While in a Demonic Rage, you gain the following benefits

• You have advantage on Strength & Charisma checks and Strength & Charisma saving throws
• Your Strength and Charisma scores increase by a +2
• When you make a melee weapon attack using Strength, you gain a bonus to the damage roll that increases as you level up. Initial damage is 1D4 Force Damage + 1D4 Fire Damage, this increases to 2D4 Force + 2D4 Fire at level 8 and 3D4 per damage type at level 16.

At the end of each turn where the player choses to remain in this form they must make a Charisma Saving throw, the starting DC for this save is 10 however for every turn spent in a demonic rage the DC increases by +2. The Demonic Rage can be dropped as a free action whenever the player choses or is Unconscious, however if their character fails their Charisma Save they become possessed by the demonic entity that gave them their rage.

This Chaotic Evil entity has the same base stats as the player character they have possessed expect heightened with a plus +4 (increase every modifier by +2) to every ability score. This entity also has the same feats, abilities, proficiencies, skills and AC as the player character as well as (if not already)

• Senses - Truesight (120Ft), Darkvision
• Damage Resistances - Cold; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks
• Damage Immunities - Fire, Poison
• Condition Immunities - Poisoned, Charmed, Frightened
• Magic Resistance - Advantage on saving throws against spells and other magical effects

The possessed character will act on an instinct of violence but also preservation, they will target whoever or whatever is the biggest threat to ending their control of their vessel, this can include enemies and allies however with an underlying malicious intent. This possession will remain for 1 minute or until the possessed character reaches 0 hit-points or is Unconscious.

The player can enter a Demonic Rage as many times as they wish however the DC for the Charisma Saving throw at the end of each turn will only reset back to 10 after a Long Rest, hence if a player makes a DC18 save and then ends their rage if they Demonic Rage again before a Long Rest the first saving throw they will have to make would be a DC20. 

Notes

• You can enter a Demonic Rage regardless of wearing heavy armour or not
• You can still use and concentrate on spells in a Demonic Rage
• You are not resistant to bludgeoning, piercing, and slashing damage from magical weapons
• Your Demonic Rage does not end if you haven’t attacked a hostile creature since your last turn or taken damage since then
• If the character is possessed then no spell can undo the possession (dependent on the choices of the DM)
• The possessive demonic entity has access not only to the physical and mental abilities of the player but of their memories too, so they would be able to make consciences decisions with their actions (such as using fire damage against an enemy they know has a weakness to it or bringing up personal details of an ally to weaken their mental state)
• A possessed entity does not get the perks of Demonic Rage, they are not in a Demonic Rage they are just a Demon