by Cellerworld
This is technically not well suited for the Quest System at the moment, but more advice for Campaign and Adventure gameplay.
When a character drops to 0 hit points or below they roll a const save DC11 or half damage on failure gaining a level of exhaustion. They always enter a “near-death state”. In this State, you are always treated as if you have 0 HP
This also introduces a “knockout” action to knock a character unconscious for 1d4 hours, if that character is in near-death state after the attack has resolved. Healing does not wake a character from this. The target of the knockout action makes a DC 10 or half damage Con Save. The save is done with disadvantage if the damage type is bludgeoning.
Since healing should keep character above 0 now, it should be buffed slightly (Exploration below).
All healing spells using dice get exactly one extra dice. Meaning Healing word for example has 2d4+mod when cast at level 1 and 3d4+mod when cast at lvl 2.
Berserker Barbarian does just not gain exhaustion for his rage with these rules.
Note:
With this, I would recommend loosening up the exhaustion regeneration a bit. Additionally to long rests the first time in a day when a character is regenerated to full health after dropping to near-death by any means, they recover 1 exhaustion.