Bolster Ally - Cantrip that gives temp HP

[Greywander]

When the Artillerist Artifier and Twilight Cleric were released, both with ways to grant the whole party temp HP every round, it was a game changer as far as party optimization goes. Like, you don't need it, we've gotten along just fine without it before they were released, but the amount of damage reduction it provides adds up fast. Every optimized party should have one of these two. Which is a problem. As the saying goes, if no one picks it, then it's underpowered, and if everyone picks it, then it's overpowered. I would hesitantly say that yes, these two options are, in fact, overpowered, at least, compared to what was the baseline beforehand. But instead of nerfing these two subclasses, we could try and instead raise the baseline back up to match them.

To that end, the most logical thing to do was to make a homebrew cantrip that gives a similar benefit: temp HP, to multiple party members, as a bonus action. I think this would be an appropriate cantrip for bards, clerics, and artificers.


Bolster Ally
Evocation cantrip
Casting Time: 1 bonus action
Range: 30 feet
Components: V
Duration: 1 round

You speak a word of encouragement to one creature of your choice within range, raising their spirit and boosting their vigor. If the target can hear you, it gains 2d4 + 1 temporary hit points until the end of your next turn. While the target has these temporary hit points, they also gain a +1 bonus to AC and saving throws.

You can bolster more than one creature when you reach higher levels: two creatures at 5th level, three creatures at 11th level, and four creatures at 17th level.

A few notes: This cantrip has the advantage in range over the artificer. Otherwise, it's slightly worse in terms of the temp HP granted (which is fair, given that both of the other abilities cost resources to use) and initially only targets one ally. Also, the temp HP is lost at the end of your next turn (it's at the end of the turn rather than the start just in case you engage in friendly fire with an AoE on your next turn), instead of lasting indefinitely. I added a minor bonus to AC and saves, since both the artificer and the cleric abilities give half cover at higher levels (+2 to AC and DEX saves). It uses a bonus action like the artificer's ability, but remember, it's a spell, so you can't cast a leveled spell with your action on the same turn. I also gave it the condition that the target has to be able to hear you, which is fairly niche but could come up.

Overall, this is a weaker option, so Artillerist Artificer and Twilight Cleric are still optimal, but now at least they're not the only options. If you aren't worried about being optimal, this allows you to get a similar benefit while freeing you up to play something other than those two classes/subclasses.

[JNAProductions]

The issue with this is Magic Initiate or similar.

As a full-caster, I might take this, but I wouldn't spam it.

As a Fighter? What else am I using my Bonus Action for?

[Greywander]

Even then, though, I feel like that's still suboptimal compared to just having an Artillerist Artificer or Twilight Cleric in the party. Yeah, picking it up via a feat or racial trait on a martial character is probably the best way to do it, but it's still slightly worse than the official options.

[Yakk]

It should be an action. (Combat) cantrips are non-martial replacements for the attack action. (Shillelagh is a hybrid utility/combat cantrip; hence the 1 bonus action. It does nothing until you consume your action, however).

And the +1 to saving throws is noise; temporary bonuses shouldn't be that small.

Start it as 1d6+attribute modifier. Scale it by +1d6 at level 5/11/17.

Duration should stay 1 round. This is a combat action, not a pre-buff. (It can also be used for someone risking setting off a trap or jumping off a cliff as a bit of utility.)

[Breccia]

I agree with the smarter and faster posters. This feels too strong action-economywise to be a bonus action.

But then I remembered "hey I'm a math teacher" so I ran some tests.

I took a 1st-level fighter with chain mail, shield, and the Defensive fighting style and put them in a doorway against an infinite number of enemies that could reach the fighter X at a time. I either gave the party's healer this cantrip or didn't, and also 3 cure wounds spells, which would be cast when the fighter hit 0 hp. When the fighter hit the ground the 4th time, the fight was over, and I found the median both versions (with/without cantrip)

A) One goblin
With the cantrip, the fighter is effectively immortal. The goblin can't penetrate the temp hp with its crappy damage. This is where the cantrip is undeniably the strongest. But purely for the sake of completion, the median unprotected fighter could survive 34 rounds.

B) Two goblins
At this point, the goblins can penetrate the temp hp if they both hit in a round. No surprise here, but the uprotected fighter made it about 18 rounds before being downed for good. Meanwhile, the fighter with the cantrip lasts much longer, and the 50th percentile of the healer running dry is the 86th round. In other words, this cantrip, when spammed, gives the party over four times as many rounds to work with.

It's at this point where I decide goblins aren't strong enough to show when the spell's effect starts to crack.

C) One orc
The 50th fighter without the cantrip hits the ground and doesn't get up in round 19. The 50th fighter with the cantrip makes it to the 43rd round. That's over double.

But this still isn't a significant stress-test. Even without the cantrip, the party has a lot of time to work with.

D) Three orcs
The 1st level fighter really shouldn't be in a situation where he has 3 orcs at a time indefinitely. He'll run out of time sooner than later. Without the cantrip, "sooner" is the 9th round. With the cantrip,"later" is the 14th.

Now let's condemn the party to a quick death.

E) Two bugbears
The unproteced fighter, on average, 12 rounds. Huh. I guess the number of attacks was the big deal here? Anyhow the protected fighter makes it closer to 20 rounds. Not double, but a big deal considering the opposition.

F) An ogre
It is 100% the number of attacks. I'll get back to that later. But the unprotected fighter gets to round 14, the protected 22nd, on average.

G) An adult red dragon
Yeah, we're in hyperbole territory here. But what happens anyhow? Nearly nothing -- at the end of the fourth round, the fighter is 95% or 84% dead depending.

H) An adult red dragon, but the fighter has 50 hp this time
You can cast the cantrip at higher level, right? You see a noticeable change. 90% of the unprotected fighters are dead at the end of the 5th round. 64% of the protected fighters are. So, the median is off by about a half round.

So the cantrip's power is strongest against attrition. Without temp hp, characters take even light damage from low-threat encounters and eventually need to take short rests or healing spells. That's where this cantrip shines: it is scratch protection. The two-goblin problem for example, shows the party basically needs to stop and rest after 18 total rounds of combat. Unless the protector is scratch-proof. Then they can go on for literally an hour. An AC19 spellcaster who could spam this spell on themselves could basically fight in a war against goblins for an hour.

Which in turn brings up my second test: what if the temp hp was always three? At this point, even the goblin can get through and cause damage routinely. Yeah it'll be less, but it'll stack up...just slower.

A2) Rerun the goblin test withone goblin
Okay, seeing the difference already. Instead of being effectively immortal, the protected fighter sloooooooooooooooooooooooooooooooooo...
(deep breath)
...looooooooooooooooooowly dies, making it to round 83 on average.

B2) 2 Goblins
The protected fighter is down for the count at round 39. That means their extra time is cut to about one-third. Yeah yeah, they still last a long tie, but the benefit granted by the spell is much lower.

???) 3 Goblins?
The unprotected fighter dies, on average, in the 13th round. Oh, uh, assuming the goblins don't stab the fighter while he's unconscious, I didn't add that. Protected, they make it to round 24, but funny story: only 10 had dropped in round 13, when half the protected fighters were down. So, the spell improved the fighter's chances by fivefold? Or so? Something like that.

D2) Three orcs
This is what I think the real test is showing. If the temp hp is only 3, the fighter is down 50% of the time by round 10. The cantrip's ability to help is down to +1 round. At some point, the number of attacks just overwhelms the defense this offers.

Now the third test! The cantrip now offers 2d4+1 again, but only against the next attack that hits.

A3) One goblin
Yeah there's no change here. Or any single opponent. Duh.

B3) Two goblins
The 50th percentile is the 11th round.

Okay: now we're getting somewhere. The spell's protection is lowered to what I believe to be a reasonable level.

D3) Three orcs
The difference is, again, noticeable but not amazbeholders. The protected fighter gets to, on average, the 11th round. +2 rounds for spamming a cantrip every available non-cure wounds round doesn't seem all that bad.

So while I..hold on.

H3) The adult red dragon and the fighter has 50 hp again
The orc's result is duplicated. +2 rounds again.

So while I still don't know that "bonus action" sounds fair, I also would suggest weakening the spell with either of the options mentioned above. Simply put, I don't like the idea of a cantrip meaning that a low-level party can just fight indefinitely because their defender is "never being hurt" overly simplified there. The effects at high-level don't seem to be all that strong by any version, so the weakened version won't affect them all that much.

Hope this helps.