Lingering Rage

Anger never dies. It slumbers, takes different shapes, but it never dies. Not for you. For you, anger is a cycle. One you will never be free from, and, in time, that rage bursts forth like water from a dam: loud and destructive.

On your turn, you may enter a rage as a bonus action. 

While raging, you gain the following benefits, if you aren't wearing heavy armor. 

• You have advantage on Strength checks and Strength saving throws
• You have resistance to all physical, non-magical attacks.
• When you make a melee weapon attack using strength, you gain a bonus to the damage roll that increases as you gain levels as a barbarian, as shown in the rage damage column of the barbarian table.

If you're able to cast spells, you can't cast them or concentrate on them while raging.

Your rage lasts for 1 minute, and ends early if you're knocked unconscious. You may not end your rage as a bonus action.

You may stack your rage.

For every consecutive rage you enter, the duration lasts longer, and after stacking rages 3 or more times, you are no longer able to end the rage on your own.

Once you've raged the number of times shown for your barbarian level in the Rages column, of the barbarian table, you must finish a long rest to safely rage again. Raging without taking along rest will result the DM rolling a [roll]1d4[/roll] and on a number of their choosing, you will no longer be able to distinguish between friend and foe, attacking anything and everything in sight, going for the closest creature for you.

After four consecutive Rages, you will be forced to make a Wisdom Saving Throw (DC 13). On a failed save you will enter another rage and lose access to all rational thinking. This will continue until you succumb to exhaustion or until you are knocked unconscious.

For every 2nd rage after your limit, you will take one level of exhaustion. 
For every Excess Rage Taken without a long rest, you will gain -1 for every excess rage to all stat modifiers.