Notes from author
Here's a Faith build that I quickly made for fun.
You have an awesome lightweight, 100% physical shield, Darkmoon Talisman, Bandit's Knife with Dex for fast and amazing damage output with buffs, as well as a Crystal(or +15) PGCS which has fantastic 2H R1 attacks, combined with Dex for more damage. You could also take any kind of Straight Sword that can be buffed, because they're also really nice weapons. Btw, you don't need to have both equipped at the same time. You could level up Dexterity to 40 and keep Endurance at 40 if you want max damage but midrolls/less poise but fastrolls.
For the armor I just took the best poise while still being under the 25% weight limit, and the Crown of the Dark Sun as well as Havel's and FaP obviously. You could also use the Crown of Dusk since it does 20% extra magic damage, as opposed to the 10% that Crown of Dusk gives, and it's more lightweight as well, but at the cost of taking 30% more magic damage.
For miracles you have Darkmoon blade for a solid 474(approximately) extra magic damage, Sunlight Blade gives about 400+ lightning damage. Tranquil Walk of Peace is amazing, but probably most effective in PvP, Wrath of the Gods is good but has pretty limited use. If you want, you can swap it out for Great Lightning Spear, or Emit Force which are both pretty good ranged Miracles, and poise should *hopefully* protect you from getting staggered during the animation. It's a long way to level 137, and I wouldn't recommend going for maximum Faith from the start, because it's not that useful until you can get DMB + Talisman. I haven't tried this build out myself, but theoretically, it should be pretty Goddamn amazing. Thanks for reading all this, and I hope you enjoy it.