I've respecced to use the clawmark seal so I can use different STR weapons without borking my casting too badly. I've also given myself 13 arc. Rotten breath is amazing. Totally validates playing divine. So now I can do some damage without making a weapon flame art I want to try to make bleeding happen. How do I achieve this?
I've given myself the prereqs for Ghiza's Wheel. The weapon is hilarious but I chose it to make things bleed and I've yet to see that happen (I think. I don't know what it looks like when enemies bleed). I've also tried putting the Bloodflame Blade enchantment on the Forked Hatchet and hoeing into a giant bear's stomach with it. I didn't notice any bleeding. My damage output seemed higher on that weapon using Sacred Blade.
Do I need to take ARC? I'm spread pretty thin right now and don't have the points to spare really.
As you're new to the Souls games let me make sure you're clear on the mechanics, so I apologise if this is all stuff that you know.
Weapons that cause bleed will have the "Bleed (x)" towards the bottom of their stat page, with x representing the amount of bleed build-up caused in a single hit. For most weapons that x will be around 45 to 65. You can see your own bleed resistance at the bottom right of your stat page, below your damage reduction values, together your other status effects resistances (which are actually grouped into subcategories likes Immunity, Robustness, and Focus; make sure to press Help button to see which one is which exactly), enemies will also have their own resistances similar to your own.
To actually proc a bleed (or rot, poison, frost...), you need to deal enough hits to equal the corresponding resistance of the target, which you yourself can see when done to you by a bar that appears in the middle of your screen when subjected to bleed; that bar is not displayed for enemies, so you'll have to guess how far it's filled up. When that bar fills up fully you'll see a big splash of blood on the target and a burst of percentage-based damage (which is why it's so strong against bosses). So for example, a weapon that cause 45 bleed per hit will need 7 hits to cause bleed on Margit who has 316 bleed resistance according to the wiki. There is no corelation between size of the weapon and bleed build-up strenght, which means a slow weapon will be much worse at causing those bleeds than a faster one, they'll need the same number of hits but obviously a dagger will get you there much faster than a Colossal sword.
BUT, as is the case for you, the bleed build up you've inflicted on an enemy will gradually go down over time, meaning that if a boss does a long combo, hits you forcing you to back off to heal, then does another long combo that you need to stay away from, any bleed build up that you might have caused him will likely have completely disapeared by the time you attack him again, preventing any bleed damage to proc. This means that bleed works best with steady aggression and fast weapons that can get multiple hits in whenever you have a window of opportunity rather than slow ones that can barely squeeze one hit in between boss combos. A result of this is that our previous Margit example is much more likely to require 9 to 12 hits to proc bleed, as he's not going to stand there letting you wail on him uninterrupted.
As for scaling, the amount of bleed caused by a weapon scales with arcane
only if that weapon has an arcane scaling in its stats. This means that the Winged Scythe, a faith weapon that causes bleed (55) but has no arcane scaling, will never see an increase in that bleed value. On the other hand, the Uchigatana causes bleed (45) but natively doesn't scale with arcane, but you could put a bleed ash of war (such as bloody slash) which would give it arcane scaling thus allowing that bleed build up value to increase with your arcane stat. Ghiza's Wheel has Bleed (70) but doesn't scale with arcane, BUT its weapon art causes a lot of hits in rapid succession, making it proc bleed reliably. But as it only scales with DEX and STR, it's probably a poor choice for a Faith build like yours.
Generally speaking dedicated Bleed builds will do less damage per hits than other builds but focus on getting that bleed to proc as fast as possible to compensate (and largely overtake really once it gets going), hence why your Forked Hatchet was doing more damage with Sacred Blade than Bloodflame.
Hope this was helpful, and apologies if you already knew that stuff. I find it better to explain the mechanics so you can make your own choices rather than telling you "nah bro, your build sux, do dis instead!" with no explanations.