Hi,

I'm currently running a Baldur's Gate campaign and I wanted to give our cleric something special.

He chose the life domain and does a lot of melee fighting, but he also ended up being the party healbot a bit. I don't want him to feel forced to expend all his daily spells on healing the other PCs, which is why I created this custom "healing sword":

https://www.dndbeyond.com/magic-items/1659171-celestial-longsword

I want to give it to him once they reach Ravengard in Avernus. The story idea follows a suggestion from Dmsguild to replace Lulu with a shard from Zariel's Sword. Only that the shard is incorporated into this homebrew item and fuels its its healing magic.

Mechanically I want it to feel a bit like the holy paladin gameplay from WoW. A melee fighter who throws out small instant heals that add additional group healing when he actually uses a spell slot. I also want it to somehow scale with his levels, since Descent into Avernus goes to level 14, which is why I coupled the healing to his cleric levels.

I am just not sure how to properly balance an item like this. It should help with healing the group but it should not make the normal healing spells "useless" compared to it. But it also should trigger often enough to feel like it has a meaningful effect. 

How would you balance such an item?

Of course, this is just one person’s opinion, but as I see it, there are 2 issues with that. The first is that magic items by nature are agnostic to character abilities or levels other than prerequisites. So Magic Items are designed not to do anything based on character/class level. The other issue is that what you proposed is so much free additional healing that HP will become irrelevant to the party. If I were going to do something like this, here’s how I would think about doing it. 

I would get rid of the Wisdom check and limit the number of uses to maybe 3 charges/day. I would drop the initial healing entirely and each hit let’s you mark a friendly for up to 1 Minute. I would then have it so that you could spend an action to do a single melee attack with the weapon and expend a charge from the item to heal all marked creatures within range for a number HP=the damage dealt with the attack. If I really wanted to be generous I would not require the action and the melee attack as part of it, and instead let the player choose to do it after the attack has been made, like Divine Smite works. (So you can choose to do it after you know you rolled a crit for example.)

Alternatively, I might make it a boon from the deity. Then I could design it as a feat, which could interact with things like Levels, etc. They’re not really designed to either, but there are some things they can be programmed to do based on levels. But I would still time down the actual amount of healing significantly. 

Thank you for answering. I really like the idea to have it like a "healing divine smite". :-)

I still want the initial heal, though. Maybe like a healing version of Green Flame Blade, where a successful hit with the weapon allows healing an ally within reach for 1d4 / 2d4 / 3d4 / 4d4 depending on level.

If a cantrip can cause xd8 damage with a melee attack, healing xd4 with an attack doesn't sound too overpowered. I will also drop the wisdom check, since its main purpose was to limit the amount of healing per round he could do.

And maybe he can expand one of his spell slots when he hits to instead heal everyone marked by it. That way he still has to use his limited resources for big group heals, but can do some small healing without wasting spells on it.

The reason there are no healing Cantrips is because any free healing will upset game balance. But it’s your campaign, do what you think is right.

More related to the root issue than the sword, but I've found that providing potions of healing and allowing their use as a bonus action has gone a long way towards letting my spell casters feel free to actually use their spell slots rather than compulsively hoard them in case heals are needed.