First, Do No Hit Point Damage

[Grey Watcher]

So, I was wondering, as a theorycrafting exercise, how (in)effective could a character be in combat if they refused to do HP damage (including insta-kill attacks, since, in addition to violating the spirit of this build, they could be interpreted as doing an arbitrarily large amount of HP damage)? What would this character do when a fight broke out? Would the eventually just run out of things to do? Could they somehow have enough options to even avoid "second hand" HP damage, such as giving the axe-swinging Barbarian advantage on chopping HP off of people?

Cleric or Bard seem like they'd be the best starts. What say you?

[Shaofoo]

You could be a Rogue and use Quick Hands to be able to use items and better use of skills as well (say for grappling or disarming).

Or if you want to you can just use Nets, they are considered weapons and thus can be used with any ability that requires a weapon (of course I don't know if you add your Dexterity mod but since you aren't technically rolling anything then the damage is zero).

[Addaran]

A pure buffer/debuffer/controler/healer caster. When you don't have something to cast for the round, use bladeward or ready a minor illusion to block the enemy caster line of sight.

Protection fighting style and shield master. Stay near a friend to protect and use your attacks/bonus action to shove enemy prone. Disarm them (DMG rule) too. Eventually they should surrender (humanoids that use weapons at least).

[EKruze]

I'd highly recommend Bard for this sort of run. I've had many games in which my own Bard has gone through the night doing little to no damage to foes.

Spells like Faerie Fire, Healing Word, Blindness, Suggestion, Hypnotic Pattern, Counterspell (once you have Magic Secrets), and Polymorph can contribute tremendously to your party without and direct damage dealt on your part. Combine this with some timely Cutting Words on your reactions.

After Bard I really believe a Wizard or Sorcerer would do you better than a Cleric. If you're not going to kill bad guys then you really want to control them and a full-time healer really doesn't pull his weight in many situations. You could probably get away with casting Bless and spamming Command if you really wanted to but beyond this their non-damaging tools don't hold up to the awesomeness of Hypnotic Pattern to cut your number of foes in half.

[Discord]

I am more or less playing a character like that now in my Tuesday night sessions. The last campaign were the first Arc of our story ended, people always knew my go to was, "Scorching Ray / Fireball" so much so that it was a running joke in my group that when it came to my turn people would be like, "I wonder if he's going to Scorching Ray or Fireball"

So, with the first Arc of our campaign ended, we started up a new campaign where I challenged myself to more or less do, "Almost no damage" to be more creative with my character.

I am currently playing an Illusionist High Elf, Wizard, currently level 3, soon to be level 4.

Cantrips: Minor Illusion, Mage Hand, Mold Earth, Gust, and Control Flames.

1st Level Spells: Disguise Self, Silent Image, Mage Armor, Find Familiar (Tressym or Crow), Shield, Fog Cloud, Unseen Servant, Grease, Catapult (me and one of the front liners got an idea, of him disarming people and me Catapulting the weapon away).

2nd Level Spells: Phantasmal Force (I ended an encounter with a troll by making it think I summoned a fire elemental, it took 9 turns of attacks as it was moving, and dashing away from us), misty step, and pyrotechnics.

At level 4 I am taking the Linguist feat, to get my Int up to an 18 (we rolled for stats).

I am entirely unsure of what Cantrip I am going to take at 4th level. Prestidigitation is more or less filled by most of the other Cantrips I have already taken. Dancing Lights, Mending or Shape water more than likely.

I've been pouring over the uses of spells that don't see a lot of use.

2nd level spell Dust Devil is pretty useful, if you have some time to set up before the combat, you can mold earth loose dirt, then action dust devil over it, making it a 10ft cloud of obscurity, keeping your front liners from being attacked by ranged, and you can continue to do this every turn (Mold Earth = action, Dust Devil movement = bonus action).

So far I am getting really creative with spells and my DM awards me for being creative with the spells since I am not a damage dealer but more of a support / battle field controller. So far I think I am doing pretty well with this new creative role I've taken. It's my job to give my allies advantage or make my enemies waste their turn examining my illusions.

[JAL_1138]

Life Cleric/Lore Bard multiclass. When not healing, cast Sleep, Hypnotic Pattern, Hold Person, Charm Person, and the like. While the enemies are incapacitated, hog-tie them and take their weapons/spellbooks. Use Cutting Words to help force failed saves.

[CaptainSarathai]

I second playing a really fun Illusionist. You really do get a chance to showcase the power of a lot of the spells which get little/no play during a regular night, or get sidelined in the "spells known or prepped" lists in favor of damage-dealers.
Otherwise, going Bard and/or Rogue, Half Elf, with Performer or Charlatan could be a lot of fun. Make yourself a skill-monkey with proficiency is Thieves Tools or Forgery/Disguise kits would be pretty cool. Let the rest of the party focus almost entirely on combat. Getting about 7 levels of OoTA Paladin in there for the better aura for your buddies, plus Bless and Guidance would add to this theme (now they can effectively dump all non-combat stats and not even worry about saves).

In personal experience, I have had my Warlock "make like a Squid and GTFO" on occasion. Throwing Darkness and then stealthing out of the fight while everyone else is blind, disoriented and angry. Oh, by Pelor were they angry. It was great

[Callin]

Gust is a wonderful cantrip for this. Str dc or shove up to 5ft. Sleep for a lvl 1 spell and if using UA pick up Wiz 2 Theurge with Knowledge Domain and grab Command.

Playing this character right now actually. Though I have some damage abilities like Frostbite and Ray of Sickness.

[hymer]

Druids don't seem to have been mentioned, so I'll just do that. Presumably, minionmancy would be against the spirit of the rule, though perhaps it could be fluffed in an interesting way. The spirits of nature aren't really under the druid's control, and s/he's trying to keep people from attacking, so they won't get torn to pieces by angry wolf spirits.
Anyway, damage dealing was never the 5e druid's strong suit in general (apart from the minionmancy), and druids have plenty of control effects. Is it violating the ethos to, say, put up a wall of fire, just in case the enemy is dumb enough to run into it? Or your friends might use it to shove enemies into it? Because that would limit you somewhat.

[Citan]

So, I was wondering, as a theorycrafting exercise, how (in)effective could a character be in combat if they refused to do HP damage (including insta-kill attacks, since, in addition to violating the spirit of this build, they could be interpreted as doing an arbitrarily large amount of HP damage)? What would this character do when a fight broke out? Would the eventually just run out of things to do? Could they somehow have enough options to even avoid "second hand" HP damage, such as giving the axe-swinging Barbarian advantage on chopping HP off of people?

Cleric or Bard seem like they'd be the best starts. What say you?
I'd say that Bard, Sorcerer, Wizard or Cleric get enough non-directly harming spells to keep relevant for a whole day.
Long Death Monk would also work great for you, since it gets at-will fear as an action. So it's one-trick pony, but a good one.
Another one-trick pony (better with Sorcerer multiclass for more slots and Twin) would be Paladin: cast twinned Compelled Duel, cast Sanctuary on self, profit (while using Help or potions for allies).

Let's say you even refuse some spells which, while indirectly, still are a causality for damage (such as Dissonant Whispers used in such a way that you cause an opportunity attack).
Just with illusions, enchantement and conjuration spells, you get plenty useful on the battlefield. When you are out of juice is the most problematic moment, but you could still use Guidance, Resistance, elemental manipulation such as Mold Earth for cantrips, use the Help action for a friend, or even play the scapegoat by trying to put yourself in harm's way while Dodging.

For such as character, my two favorites would probably be either...
1. Lore Bard (illusion/charm spells, Bardic inspiration, Magic Secrets for conjuration spells or Circle of Power) / Wild Magic Sorcerer (roll feature, more control spells, Heightened/Extended metamagics) or...
2. Nature Cleric (buffs, warding feature) with either Druid (conjuration spells) or Long Death Monk (sustain a concentration buff while Fearing away).

Although any of those as single class (and others) would also work well, I just love these synergies. :=)

[Sir cryosin]

So no non-lethal damage

[JAL_1138]

So no non-lethal damage

There's no "nonlethal damage" in 5e. There's just damage. However, with a melee weapon or unarmed attack (but not with spells, and I think not with ranged attacks) you can choose to render an enemy unconscious instead of dead if your attack drops them to 0 HP.

[JellyPooga]

While Life Domain for a Cleric is the obvious choice if you want to go Cleric, I think there's more variety on the table than that.
- Arcane Domain with its turning and banishment of planar creatures, as well as a selection of Wizard spells is very much an option. Possibly better suited to higher level play though.
- Knowledge Domain grants some ability to avoid encounters altogether through judicious use of Read Thoughts and Visions of the Past, not to mention its high skill versatility.
- Nature Domain has the excellent (if situational) Charm Plants and Animals as well as one of the best reactive damage mitigators in the game in Dampen Elements.
- My personal choice goes to Trickery Domain. Blessing of the Trickster and Invoke Duplicity are both great features, but it's the Domain Spells I'm looking at; Charm Person, Pass Without Trace, Dispel Magic, Polymorph and Modify Memory. That's a very nice selection for this style of character and they're only one half of the spells on offer.

Having said that, Bard gets it done. Between an already diverse spell list, with pick-of-the-litter from other spell lists through Magical Secrets, on top of Class Features that scream "I'm not hurting anyone!" while still being useful, it's got to be Bard.

Wizard offers some nice things here, but I reckon grabbing Ritual Caster (Wizard) will cover most of the bases not already covered by Bard. Dipping for Portent is very tempting, however; that thing's a game-changer.

If it were me, I'd probably go something like Hill Dwarf Cleric (Trickery) 3/Bard (Lore) 17, picking up Ritual Caster (Wizard) at the first opportunity.
- Bard 6; I'd grab Beacon of Hope and Plant Growth.
- Bard 10; probably Passwall and either Wall of Force/Stone.
- Bard 14; Forcecage (duh) and either Etherealness or Plane Shift, depending on who else is in the party.
- Fill up the rest of the Bard Spells Known with anything that;
A) Isn't a Wizard Ritual.
B) Isn't a 1st or 2nd lvl Cleric spell
C) Doesn't do HP damage (e.g. No Dissonant Whispers or Animated Objects)
D) Doesn't directly help someone else do HP damage (e.g. No Hold Monster, unless your sole use is to help others run away)

[Demonslayer666]

Pretty ineffective IMO, but perhaps a grappler/wrestler that ties people up, or someone that uses a lasso.