Thought I'd start an admittedly silly thread idea, converting characters and mechanics from the game Darkest Dungeon to pathfinder..
I put this in 3rd party because it's going to use a lot of spheres of power stuff.
A Few Classes
Crusader: Dirt Spattered Angel Paladin wielding full plate and using a Great-sword. Also you could grab Sphere Paladin if you don't want vancian casting.
Highwayman: Conscript with the Scout and Sneak Attack specialization and the Guarded Shooter drawback on dual wielding (also the Duelist Sphere for open vein and Fencing to get more sneak attacks). I'm sure there are probably better options for the fluff but in terms of its role as damage dealer that uses attacks for everything it's useful.
Plague Doctor: Scholar, Possibly of the Doctor Archetype, or the Alchemist. Scholar has the advantage of flash bangs being at will meaning you can toss them at everything you don't like, whilst the Alchemist's titular ability and higher bab and hit points mean a lot.. But if there's an archetype for alchemist that replaces Mutagen then take it.
Vestal: Cleric. Probably taking the Light and Healing domains. Total healer that heals all the things.
Arbalest: Scholar with Martial Training with the Sniper Sphere, making singular, deadly called shots at people and going around with a big bow and a breastplate.
Marvin Seo's mod classes
Thrall: Darkness Defender. Going all in on berserking and getting as many Brute and Berserker talents as they can, also grab duelist and bloody slasher if you want some bleeds.
Falconer: Scholar with Martial Training with the Barrage sphere, and specializes in combining Scouting and deadly barrages of arrows together.
Mechanics
Stress: Characters have a secondary hit point pool of 'Stress". Players can take stress damage from multiple sources. On average, players have a stress pool between 10 and 20 (not sure about particular numbers)
1: Some monsters have abilities specifically designed to deal stress damage.
2: When a monster confirms a critical hit against the character they make a will save or take 1 stress damage.
3: some other abilities or circumstances can increase stress.
Stress can also be healed in a number of ways
1: confirming a critical hit or maxing out the dice of a given ability (Example, a healing spell rolling a perfect 8 on any of the D8s) will heal 1 stress.
2: Some abilities might be able to heal
3: similar to caring for a partner using the heal skill. during a rest you can use the Diplomacy skill to give a pep talk that can heal stress.
Afflictions
When stress is maxed out once, the hero rolls a save. and has a chance to gain either a Virtue or an Affliction.
Afflictions They take a -4 penalty to certain rolls or statistics, and must roll each round in order to avoid a negative outcome.
Masochistic: AC and saves against hit point damage. Failed saves will cause you to actively try to get yourself killed, presenting yourself as a target, running up to the strongest enemy you see and giving them an attack of opportunity, or if you get a natural 1, turning your weapon on yourself and taking 1/2 weapon damage.
Fearful: Attack rolls and will saves against fear. Failed saves will cause you to panic and try to get further away from the cause of your fear.
Irrational: Effectively anything, rolled randomly at the start of your turn
Abusive: Will Saves (other than your affliction save). Failed saves will cause you to choose one of your partners at random and berate them, causing them to take stress damage.
If you max out your stress a second time after gaining an affliction, you are forced to make a fortitude save, or be reduced to 0 HP from a Heart Attack. You are stable, but may need immediate medical treatment. If you max out your stress a third time, your character makes a second fortitude save at -4 or immediately die. This can go on, giving an extra -4 to the save (so the 4th time would be -8, 5th would be -12, etc.)
Virtues give a +4 bonus to certain rolls and statistics, and roll each round to gain a free bonus. You also heal 1/2 of your total stress and no longer take any penalties if your stress is maxed out again.
Powerful: Attack and Damage. Successful virtue rolls will allow you to give your virtue bonus to an ally for 1d4 rounds.
Stalwart: Will Saves. Successful virtue rolls will heal 1 stress from one random ally.
Vigorous: AC and Fortitude saves: Virtue rolls will heal you 1d4 damage.