I'd like to share my idea on how to use the druid frame to build a Dwarven Rune Priest.
In my mind these are tough little buggers that can stand toe-to-toe if required but who generally have weird constructs running around and can blast stuff from a distance, whilst patching friends up if needed. When they're out of combat they forge trinkets and often powerful artifacts.
So a jack of all trades if you will.
I've been playing a human war-priest cleric and found all I was doing was 3 action party heals, which I was finding particularity unrewarding. Now this was probably my fault, I wanted to be the off tank with the ability to heal, but our party started to require that was all I did. We are rejigging the party a bit to share the heals around.
I have an agreement with my DM that the key word 'animal' can be exchanged for the key word 'construct' wherever it turns up in the druid tree.
This isnt an optimised built but suits my play style of always having a useful turn, without the need to spam the same action over and over again (something that bores me).
The druid frame is often overlooked because of the nature baggage that it tends to bring along. But upon closer inspection this can be spec'd in a couple of different ways that are quite effective. In the old 4e D&D talk it can do these roles nicely; controller, striker, leader.
I'll only run this guide to level 5 as you kind of get the idea from that point onward.
Level 1
Ancestry - Dwarf; Heritage - Forge Dwarf; Ancestry Feat - Dwarven Weapon Familiarity
Class - Druid; Druidic Order - Animal (Construct) - I am using the animal companion Bear for the nice extra damage it brings with its Working Together d8s damage and its grab. Also it has a lot of hit points to act as a damage sink. It will be fluffed to be a Iron Steam Golum kind of thing.
Background - something that provides Wisdom boost, I picked field medic for the very good feat Battle Medicine along with the Medicine skill.
Starting Stats - Str 16, Con 14, Dex 12, Int 10, Wis 18, Cha 8
So this is the basis of the Rune Priest. Pick up a Warhammer, Breast Plate and Steel Shield and you wont be found lacking in melee. I'd pick one attack cantrip like Acid Splash or Electric Arc and the rest support cantrips. As we are sharing the healing I'd pick up 1 Heal and also Summon Animal (Construct) to stay in theme. I pick up Crafting for theme and Athletics cause it's always a good one to have.
Level 2
Druid Feat Order Explorer Storm - thinking of level 6 when there isnt a good class feat to pick and will then pick up the Storm focus spell and a second focus spell point. Otherwise one of the two meta magic feats, reach or widen, are always useful.
Skill Feat Alchemical Crafting - for the fluff and there are some nice formulas Cheetah’s elixir for speed and of course Elixir of life.
Level 3
General Feat Fleet, because moving around at 20' sucks
Skill Increase Crafting, because I'm shooting for magical crafting in a level
At this level you get to pick the always excellent Flaming Sphere, a damage spell that just keeps on giving. I might switch between a heightened Heal or Summon Animal (Construct), which in turn opens up a level 1 slot for Hydraulic Push. Expect to be getting striking or potency runes on you your warhammer for extra chance to hit or dealing extra damage.
Level 4
Druid Feat Mature Animal (Construct) Companion, your companion gets better damage, but most importantly can now take an action without you needing to use Command an Animal action yourself.
Skill Feat Magical Crafting. This feat starts to open up a whole range of new options for supporting the party. I like Hat of Disguise, Feather Token Ladder and of course Healing Potion. You will also start to be responsible for adding items to the party's equipment.
Level 5
Skill Increase Whatever you like but I'd be thinking Athletics or Healing.
Ancestry Feat Dwarven Weapon Cunning is a nice add on your crits and with Hammers you get to knock stuff prone. Added to the Push ability from Hammers you are starting to now add control effects to enemy in melee.
Stat Increase Str, Dex, Con, Wis. That being said if you're concerned about your craft rolls you can add Int over Dex but overall I find Dex to be more useful more often.
Level 3 primal spells are really nice, Fireball is a first pick for any caster that gets their hands on it. With your very high Perception you are often going before the mobs in the first round which is when you might drop this bad boy. Summon Animal (construct) heightened gets you the great Animated Armour, there is the excellent control spell Sticking Cloud, Haste is always a crowd pleaser on your striker melee character (or yourself). There's probably room for a 2nd heightened Heal to level 2.
I'll stop there but I hope this gives some ideas on how, with a little support from your GM, you can take one of the core classes and turn it into something a little special.
My only concern is that, unlike most creature types, constructs have a lot more immunities than animals, so that is actually a fairly substantial upgrade in power. If the swap is simply cosmetic, and your constructs lack the typical immunities and rules that they are supposed to have, then cool.
A construct is an artificial creature empowered by a force other than necromancy. Constructs are often mindless; they are immune to bleed damage, death effects, disease, healing, necromancy, nonlethal attacks, poison, and the doomed, drained, fatigued, paralyzed, sickened, and unconscious conditions; and they may have Hardness based on the materials used to construct their bodies. Constructs are not living creatures, nor are they undead. When reduced to 0 Hit Points, a construct creature is destroyed.
Just exchanging 'animal' for 'construct' does not seem fitting
the anathema does not quite fit anymore
Also for someone who focusses on fighting with an artificial companion and focussing on advanced crafting methods a druid is probably not a very good chassis (imo)
Having a construct as 'Animal Companion' of sorts makes perfectly sense and I understand that there are not many good options for it out there
I would point out that druid's can't wear metal armor as your rune priest is.
I believe the forthcoming Advanced Player's Guide has an archetype focused on animal companions. Perhaps another class plus that archetype, with similar edits around the animal trait, would bypass the ever present natural theme of druid?
I’m feeling as though wizard may be best for your theme. Wizard is Int based which is great for all of the Repair checks you'll need to be making on a construct companion. Int also seems appropriate to the theme of knowing all about how to manipulate runes.