Now that you mention it, just creating an "item" that is effectively just an armor flavored as tattoos has its own advantages.

For example, at higher levels the character could apply armor runes directly to their body. Thats pretty cool in and of itself and also in tune with the idea of expanding the tattoo with different effects. All with minimal effort and without having to worry about balancing issues because the rules are already there.

Just noticed from the other comments that my option a is just the same as an archetype without the archetype part... so yea, still have to get used to how PF handles these things myself 😅

As far as I understand it, archetypes are more of Pf2e's way to do 'multiclassing', where you choose feats from an archetype instead of your normal class feats.

So you're right, there is no direct correspondent to DnDs subclasses in PF2e. But many classes still have subclass-like specializations. They have different names for each class, for example 'ways' for the gunslinger, 'instincts' for the barbarian or 'arcane theses' for the wizard. These in themselves tend to have a little less meat than 5e subclasses, because you still have a lot more customization options with your feats. Mostly they modify a core element of the class and also give acess to specific class feats.

Sadly, the fighter seems to be be the odd one out and is designed to not have any such specializations. Maybe so it can be a beginner friendly class that doesn't overwhelm the player with choices..?

So as I see it you might:

a. just make some appropriate fighter feats for your culture that any fighter can choose (with whatever restrictions you place on that as the GM, regarding backstory, etc.). This would be the easiest in my eyes, as you could orient yourself on existing feats for how much these should be able to do.

b. you could make this an ancestry/heritage thing, seeing that it should be tied to a culture. Maybe not exactly what you want, if it is supposed to be for fighters only. Could work as just a generally available ancestry feat/series of feats that players can choose. However these often don't make mayor changes to a character and rather give a small bonus to something.

c. make a new class that gets all the same stuff as a fighter, except for some things you replace with your own homebrew. This might get a bit more complicated than creating additional feats.

d. figure out how to modify the entire fighter class to offer a subclass-like choice. I wouldn't know where to start on this one. This would easily break something in how the game is balanced and feels like a job for people who are on a level of understanding this game on par with the designers at paizo.

Just as a final note: I haven't really started to homebrew much in PF2e myself, so my ideas on this might not be super accurate.

I think (some of) the hostility towards homebrew might come from the fact that PF2 plays very much "numbers first" in the sense of balancing. So I feel this is one of its greatest appeals for players of the cellar lizard game who couldn't stand the wobble of that system. When those people associate "homebrew" only with "fixing the dang game" of course they get confused when people try to "fix" a game that doesn't have any such glaring mechanical oversights.

That's of course not helpful though. As I see it, mostly people homebrew because they are going for a different experience but with a familiar game system or just 'cause it's fun to try and see what you can do with the game.

I've only been running PF2 for a short while and haven't really tried changing anything as I believe I should know how it works before messing with it. In other systems I've homebrewed quite a lot and optimizing the balancing was more of a helpful creative framework and never the sole point of it.

So yeah, I like the idea of encouraging people to share their rule variants. Wasn't this the whole point of having a better open license anyway? So everyone could share their custom stuff without worry and everyone else would have a better and richer game for it? 😁

(with homebrew here I mean changes to the core rules only and not adding your own creatures/items/... That I already do because it's baked into the core rules in PF2)

I personally think so. It is in many ways similar to 5e but a bit denser on rules. It feels like the designers really wanted to make sure that there were no weird corner cases. And while there is a lot of them, the rules all seem very logical and consistent. So when playing it feels a bit more "mechanical" or "game-y" but also less wonky than 5e can be. It is a somwhat different experience than 5e and the rules are available for free at Archive of Nethys. But if you should pick it up really depends on whether your group is unsatisfied with DnD or itching for something new. Our group changed over after trying a one shot and because our DM was getting a bit bored with 5e.

Yeah, just a case of sausage fingers.

I mean, that would depend on how everything interacts with those strings.

Are they everywhere and you just pluck them with your fingers basically in thin air? Then mages could just be shredding air guitars all day, which might be hilarious if thats what you want to go for.

Do the strings vibrate with every sound that is made? Then there could be different ways of doing magic. Instumental, singing, speaking, clapping, etc.

Is it only music? And would natural sounds also be able to cause magical effects? Or is physics even the other way around in your world? Do sounds just occur and the right whisper makes the trees sway and a loud rumble can make the earth quake?

From there you could get into a Tolkien-like area, where the world was just sung into being in the first place.

Just to throw a few questions/ideas out there, where this might go.

I don't really have a "true" origin story for the setting of my fantasy ttrpg home game. But of course everyone that lives in the world has their own theories about the origin of everything. I like the creation myth of one of my dwarven cultures best/have it the most worked out, so I'll share that here:

In the beginning the world was just an empty ball of clay. And nothing was and nothing could be. For noone was there to make it be. Yet still there was the Craft in the world and it was so great, that the First Beings arose, shaping themselves from the clay of the world.

There arose Noble Dhum. And so great was his Craft that he made himself the greatest toolsmith and the greatest stone cutter tat ever could be. Lord over all the mountains he then raised and everything thereunder. Ruler of everything in the newly made world.

And there arose Wise Erdake. And so great was her Craft that she made herself the greatest fountain of knowledge that could ever be. Knower of all secrets and most learned in the languages and runes she created. Cleverest engineer of mills and machines. Misstress of the rain and all the bodies of water she set flowing.

And there arose Exuberant Kruf. And so great was their Craft that they made themself the origin of all plants, the sun and moon and all the forces of nature that shook the world from its stasis. Driver of every storm, fuel of every fire, passion of every bolt of lightning, the hammerstrike behind every shake of the worlds stone.

And there was Wild Naveg. And so great was her Craft that she made herself the strongest warrior and the fastest hunter that ever could be. The bringer of all death, the champion of all fights. Most dangerous predator of all the animals she created.

And so these Four-that-created-themselves shaped the world, each according to the nature they had made themselves to posess. And each they united with each of the others. And from those unions arose their descendants, the six original clans of the dwarves. Seeing that these descendants posessed only a small fraction of their Craft, Dhum took to leading them and Erdake took to teaching them. Kruf however made new beings by themself. However, almost devoid of Craft they went of to live among the plants of their forests and graslands. And so the humans and halflings came to be. And Naveg as well made new beings by herself. However, equally devoid of Craft they went off to fight against another in lands far from the lands of the first dwarves. And so the elves and orks came to be.

And for long the Four-that-created-themselves lived among the dwarves. But the dwarves grew lazy and instead of striving to better their craft so they might one day reach the greatness of their creators they demanded their gods solve every problem for them with their great Craft. And so insolent and bothersome grew the dwarves that the gods retreated from their lands and withdrew to the far reaches of the world. Noble Dhum went far beneath the moutains, deeper than any dwarf could dig, to practice his Craft in peace. And Wise Erdake sank far beneath the ocean, deeper than any dwarf could ever dive, to practive her Craft in peace. Exuberant Kruf went to walk among all living things, present in every gust of wind yet never showing themself to any dwarf or other mortal being, to practice their Craft in peace. And Wild Naveg went to roam the battlefields and graveyards of the world beyond deaths door, only to be reached by dwarves and other mortals after they left behind their lives and troubles, to practice her Craft in peace.

And ever since then the dwarves have to strive to regain the Craft. And only if they are diligent and virtuous may those-that-created-themselves look apon them with grace and aid them in the perfection of their Craft.

Wow, that sounded shorter in my head. Anyway, long story short: four beings made themselves then made everything else. The dwarves are their children but then drove their own gods away by being lazy.