I’m kind of on a custom class kick. Humor me.
The Lucky Motherfucker has a d6 hit die, and advances using the Fighter’s experience table. All of the Lucky Motherfucker’s saving throws advance as the Fighter’s save versus Magic does. Paralyze, Poison, Breath, Device, and Magic all begin at 16, drop to 14 at level 4, then to 12 at level 7, and so on.
It kinda sucks to be a Lucky Motherfucker, actually. Except for the fact that you almost never die, even when you really should have.
Lucky As Fuck: Anytime the Lucky Motherfucker takes damage that would reduce it below 0 hit points, it is reduced to 0 hit points instead. Any time the Lucky Motherfucker is subject to an instant death effect, it is reduced to 0 hit points instead. Only damage taken at 0 hit points can reduce the Lucky Motherfucker below that threshold.
Lucky as Fuuuuuuuck: The first time during any game session that the Lucky Motherfucker reaches 0 hit points, they gain 1d6 hit points. Each subsequent time the Lucky Motherfucker reaches 0 hit points, they must roll 1d20. If they roll above the number of times they have already reached 0 hit points this session, then they again gain 1d6 hit points. Otherwise they remain at 0 hit points, and cannot benefit from the Lucky as Fuuuuuuuck ability again until they’ve been healed to above 1 hit point.
So the first time is automatic. The second time you must roll above a 1. The third time you must roll above a 2. And so on, and so forth.
Some Backstory: Awhile back, I played in a game run by Brendan S. In that game, a character who hit 0 hp had to make a roll-under Constitution check to see if they lived or died. After losing several characters, I rolled a character named Hawkwind who was blessed with 18 Constitution.
Hawkwind ‘died’ more times than I can remember, but each time he died, he had a literally 90% chance to pop right back up again. It was broken, and unfair, and awesome. Obviously it’s not ideal for this ability to be the result of a random die roll made at character creation, which is why Brendan changed the rule so that each “near death experience” reduced the character’s constitution by 1. But perhaps if the entire class is designed to suck at everything except surviving past when they ought to die, it can be a fun addition to the party rather than an annoyingly unfair advantage.