DnD campaign

In an effort to make the game a bit more realistic and challenging in terms of combat, we've decided to introduce a maiming mechanic. The idea is that you shouldn't be able to take a massive hit in a fight and have no permanent damage afterward. It will create some interesting roll-playing possibilities as well, as you may end up with a one-armed or eyeless character after a particularly brutal fight. This should help keep characters dynamic, and prevent fights from being reckless slug-fests.

Here's how it works mechanically:

If a source of damage deals damage greater than or equal to your constitution score plus your proficiency, your character has a chance of being maimed. When this happens, you roll a d6 to determine the severity of your injury. You may then roll a Saving Throw appropriate to the nature of the damage, on a failure you take the result of the d6, on a success you take 1/2 the result of the d6 (5-6 is a 3, 3-4 is a 2, 1-2 is a 1). The descriptions below are kept general, with the idea that the type of injury and consequences will be very dependent of the type of damage received (bludgeoning, slashing, piercing, fire, etc.) and the manner in which it was dealt.

On a roll of 1 or 2, you receive a light injury, conferring some penalty for the remainder of the encounter
On a roll of 3, the damage is a little more severe, and you are somehow until you take a short rest
On a roll of 4, the damage worsens further: you are now debilitated until you take a long rest
On a roll of 5, you receive a serious injury, debilitating you for multiple weeks, possibly months.
On a roll of 6, your injury becomes catastrophic: you are now permanently debilitated in some way

If the entity dealing the damage is dealing non-lethal damage (i.e., a person in a bar fight, someone attempting to render someone else unconscious), the result of the d6 roll is reduced by 2. Thus, it becomes impossible to receive the effects of a 5 or a 6 when your adversary is not trying to kill you.

Depending on the circumstances, the DM may also decide that if the damage is not dealt on a critical hit, the d6 roll may also be reduced by two. This is left to the DMs discretion, however.

Here are a couple of examples:

Davey Sprocket, a plucky human fighter, is facing off against Gordok One-Eye, a fearsome orc. Gordok crits Davey with his battleaxe, dealing more damage than Daveys constitution score plus proficiency in damage. Davey rolls a 6 on the maiming-dice, meaning he receives permanent damage. Because Gordok was using a battleaxe, the DM decides that Davey loses an arm.

Shireen, a drunken elven cleric, is causing a ruckus in the town square. Moko, the constable, attempts to subdue her with some non-lethal damage from his cudgel. He hits her harder than expected, and deals more than her constitution score plus proficiency in damage. Shireen rolls a 6 on the damage table, and then subtracts 2 since Moko was not trying to kill her. Thus, she gains the effects of rolling a 4, and is debilitated until she takes a long rest. The DM decides that since Moko was using a cudgel, Shireen received a mild concussion.