Edge-Dancer

Many features that harm the player character at the benefit of extra damage/utility, ability to survive while in otherwise deadly situations, Flexible resource pool, unique play style that can fit a more risk based fantasy, and I think Flavorful features.

Adrenaline

Beginning when you choose this archetype at 3rd level, you gain an adrenaline pool of constitution.Mod + fighterLevel (min1).

When you roll a D20 in combat or an attack is made on you, you may spend adrenaline points up to your proficiency modifier to add or subtract the amount of points used to the roll.
When you would reach 0 HP you may instead Spend 3 adrenaline and be reduced to 1 instead.
If you do not have enough adrenaline points for an effect you may take unblockable damage equal to 3x the adrenaline points you are missing and use the effect anyway.
If using an effect that would consume adrenaline  points would make you go to zero HP you  may instead use a Hit die per missing adrenaline point.

at the end of your turn if you have 0 Adrenaline points take 1d4 unblockable damage unless you spend a Hit die, you can use an action to convert one hit die into 1 adrenaline, if you have 0 hit die you can use this action at no cost.

all adrenaline recovers on a short rest.

 

Dancing on the edge

Starting at 7th level, once per round you can move an additional 5' per adrenaline point spent on this effect
While at 1 HP If you hit a target with an attack, you can roll critical damage at the cost of 1 adrenaline.

Adrenal Twist

starting at level 10, when you deal damage you can spend adrenaline  to deal 1d6 additional damage of the same type per spent adrenaline
When you succeed a saving throw that would deal damage to you, you can spend 1 adrenaline to take no damage instead.

Adrenaline Spike

Once per round when you take damage regain 3 adrenaline.

200-BPM

starting at level 18, when entering initiative gain one action surge (max 3), action surge grants an additional bonus action.