Can I use an object to provide temporary hit points?

Question

Some background first... We had a discussion in our group about object HP and using that as a kind of temporary hit points. It came about when my halfling was hiding in a barrel and a bandit hacked the barrel to pieces to get to me. In the next session another player showed up with a length of chain fitted to his armor. Our DM saw he'd described it well enough to show he'd given it serious thought and let him have the 10 HP of the chain.

The DM used this to his advantage by having the first strike of the first encounter hit that character and applied the damage (which was a secret roll that happened to deal 11 damage), that broke the chain. This worked to everyone's satisfaction: the player got to feel like his clever idea did something (saved him from a powerful attack), the DM got to make his encounter seem more threatening and he restored the game to the pre-chain state. So far, so good right?

A third player in the group decided he wanted to set up a chain like the other character, the DM ruled he couldn't because (a) they didn't have the time (the other chain was placed between adventures) and (b) the character didn't have the skills/tools (the one with the chain has smiths tools or something- I can't remember, they aren't my characters). Problem avoided?

The next session the player who didn't get to use chains came back- he'd picked up the tool set between sessions and basically maxed his encumbrance on chains. First encounter- the DM strikes him, 11 points of damage ALL of the chains he's wearing are cut free... the gold spent on them is wasted. He rules- no matter how many chains were attached to armor, the character can only benefit from one.

The DM allowed the 1st chain because the player was inventive and thoughtful, so he ruled by fiat. I think if we had all tried the single chain he would have allowed it, but this (wearing a dozen or more) was obvious abuse.

So now I've been thinking... I can't find an "official" rule for or against doing this, the closest would be the cover rules, but I think in this case using the object HP ends up being less of a mess than trying to use it as transportable cover (which would give an AC bonus etc). Does anybody know of an actual rule that would cover this?

Answer 1

It's called Armor.

What do the Rules say? I think the applicable rules are armor rules. The intent behind wrapping chains around yourselves is protect yourselves. That is the job of armor.

Chain fashioned around your self are similar (enough) to Chain mail or ring mail, both are heavy armor. Chain mail requires strength of 13 and imposing disadvantage to stealth. For that you get an AC of 16. Those chains have no HP, and no mechanism for it to be destroyed for simplification reasons.

Adding other objects to the character to act as armor isn't necessarily outside the rules, but isn't something the rules consider. Which means that what happens is left up to the DM. The most appropriate rules for this sort of thing are the armor rules, not the object HP rules. Adding armor in this fashion should affect AC, not add additional HP, and depending on the amount of chain likely have stealth implications.

Object Rules

The barrel is what item HP are meant for, a situations that happens to come up where someone needs to destroy an object. The rules on objects are for objects, not armor. The rules for objects can be found in the SRD ( official ) in Game Mechanics under Objects. Reading them it is clear that the intent is an item caught in the cross fire, or the characters try to destroy an object. It isn't meant for items that are worn to provide temporary hit points.

This path might inspire your DM to employ armor/weapon damage house rules. Your swords might suddenly break or shields shatter. That is the logical extension of applying these HP rules to all things in the world.

Ultimately, it's the DM's Call

To apply armor rules or object rules is the DMs choice. Armor rules are the ones intended for defense, but there is nothing preventing him from applying object rules the way he has already.

Answer 2

There are no rules allowing this. However that not an issue as RPGs are not about playing the rules of the game but rather they are about providing tools to use to run a campaign.

Page 6 of the Player's Handbook describes the basic process of how the game works during a session of play.

1. The DM describes the environment
2. The players describe what they want to do
3. The DM narrates the results of the adventurers' action.

The rules are tools the help the DM narrate the results. In the absence of a specific rule, the DM will have to make a decision based on his best judgment.

This is reinforced by page 5 of the DMG where the author give explicit advice on how to handle situation not covered by the rules.

The rules don't account for every possible situation that might arise during a typical D&D session. For example, a player might want his or her character to hurl a brazier full of hot coals into a monster's face. How you determine the outcome of this action is up to you. You might tell the player to make a Strength check, while mentally setting the Difficulty Class (DC) at 15. If the Strength check is successful, you then determine how a face full of hot coals affects the monster. You might decide that it deals ld4 fire damage and imposes disadvantage on the monster's attack rolls until the end of its next turn. You roll the damage die (or let the player do it), and the game continues.

It just not possible for any set of RPG rules to cover all the circumstances that could arise. A campaign is ultimately a slice of the life of a group of character who exist in a larger setting. Just as our own lives have a multitude of possibilities so do the imagined lives of the characters in your campaign.

In this specific case as you described one player showed the group through the use of the right combination of his character's skill as a smith and the resources he had avaliable, how he can temporarily improve his hit points in way that makes sense in terms of the setting.

From the details that you provided, it seems to me that it is a fair ruling. The chains require an investment of money and skill to affix, there is a penalty in terms of encumbrance, and the final result is a one time gain of 10 hit points that can't be regained until the process is repeated.

While I am sure it is disappointing to the player that it not a ongoing benefit, you can point out that he now has a new tactic that may prove critical under the right circumstances.