Moon Druid + Rune Shaper

[ATHATH]

A variant human Moon Druid can grab Rune Shaper at level 1, allowing them to cast Armor of Agathys using their Druid spell slots.

Is this something that you'd actually want to spend your spell slots on (at low levels), though? It's a way to get value out of your spell slots while transformed (you can cast it as a pre-buff before transforming and heading into a dangerous area), but is it worth it compared to just allowing yourself to be hit out of Wild Shape and slamming down Heat Metals and Spike Growths with those spell slots instead? Or compared to taking, say, Mobile to make charges easier to pull off?

Bonus question:

Comprehend Languages.
You learn the comprehend languages spell. You can cast this spell without expending a spell slot, and you must finish a long rest before you can cast it in this way again. You can also cast this spell using any spell slots you have.

Ritual Casting
You can cast a druid spell as a ritual if that spell has the ritual tag and you have the spell prepared.

If a Druid picks up Rune Shaper, are they able to ritual cast Comprehend Languages? Or are they unable to because they don't have it learned as a **Druid** spell?

[Dualight]

If a Druid picks up Rune Shaper, are they able to ritual cast Comprehend Languages? Or are they unable to because they don't have it learned as a **Druid** spell?

This one's easy; they cannot ritually cast comprehend languages, because it is not a spell they have prepared. That said, it also does not count as a druid spell, so that also restricts them. The latter is more a concern for bards, but it is a relevant distinction.

[ATHATH]

This one's easy; they cannot ritually cast comprehend languages, because it is not a spell they have prepared. That said, it also does not count as a druid spell, so that also restricts them. The latter is more a concern for bards, but it is a relevant distinction.

Could they prepare it as a Druid spell because it's a spell they've learned?

[Dualight]

It is not on the druid spell list, so no, they cannot prepare it as a druid spell

You prepare the list of druid spells that are available for you to cast, choosing from the druid spell list.

That said, if you have a feature that adds comprehend languages to the spell list of all your classes (through certain backgrounds or racial choices, for instance), you could prepare it so you can ritually cast it, but at that point knowing the spell through the Rune Shaper feat does nothing other than letting you cast it once without a spell slot without extending the casting time for a ritual.

[Sorinth]

Yeah technically you wouldn't be able to ritually cast comprehend languages, but if you asked the DM they would probably let you do it because it's kind of nothing. In the end with a free casting it's going to be irrelevant 99% of the time anyways.

As to whether AoA + Moon Druid is good, I haven't seen it in play but I feel like yes it would be pretty decent, not the most OP of builds by any means but certainly strong enough to feel good/fun once you start upcasting it.

[sithlordnergal]

So, I've played a Moon Druid from 1 to 20, and I won't lie, Armor of Agathys would work well with their Wild Shape. There are two ways a character can tank damage, the first is with AC and the second in with HP. Moon Druids tank a LOT with their HP, so being able to add a bunch of Temp HP on top of their Wild Shape is really handy. Additionally, Armor of Agathys isn't Concentration, it lasts an hour, and it scales pretty decently.

Armor of Agathys also has the benefit of being universally handy. Since you tank via HP, anything that boosts your HP is going to be handy. Meanwhile spike Growth falls flat if you don't have a good way to force enemies to move through it, and Heat Metal is useless against anything that doesn't use metal. Of course, the Druid has a LOT of other 2nd level spells that are extremely handy, but never underestimate how far a bonus 10 HP can go.

Heck, if you really wanted, you could recast Armor of Agathys a second time after being knocked out of your first Wild Shape for another 10 Temp HP, and then Wild Shape again as a Bonus Action. Sure, doing so uses up all your resources, but you effectively end up with an 88 HP buffer between you and your actual hit points if you do that. Not to mention, if you get hit in melee you end up dealing 10 points back to whoever hit you.

[RSP]

AoA is good when you have an ability to mitigate damage. In terms of going this route with a Druid for Wildshape, I’d probably suggest getting Rage to supplement it.

It’s a great defense/offense when you can stretch it out, but I’d probably just rely on Wildshape as your HP barrier and save the spells for when not using WS.

[ATHATH]

AoA is good when you have an ability to mitigate damage. In terms of going this route with a Druid for Wildshape, I’d probably suggest getting Rage to supplement it.

It’s a great defense/offense when you can stretch it out, but I’d probably just rely on Wildshape as your HP barrier and save the spells for when not using WS.

Aye, it's a Lost Mine of Phandelver game, so I'm planning to go Moon Druid 2/(Peace? Life? Twilight?) Cleric 1/Barbarian 1.