When a wickfolk chooses, they can expend one of their classes hit point die to amplify their abilities. If it's an ability check, saving throw, attack roll, damage roll, or any save their target has to make the wickfolk adds their proficiency bonus plus their stat bonus relative to the skill (Example: An attack with a strength weapon adds proficiency bonus + their strength modifier. A spell where the target has to make a saving throw adds the proficiency bonus + their casting modifier to the save dc.) 
Wickfolk can burn through multiple hit point die at once, but the proficiency bonus is only applied once. (Example: 2 hit point die used = Proficiency bonus + stat modifier + stat modifier.)

Wickfolk who expend more hit point dice than they currently have total, have their flame extinguished and suffer disadvantage on all attack rolls, ability checks, and saving throws until they take a short or long rest, or they use their action in combat to relight their wick. For (example: a level 1 fighter has 1d10 hit point, if the wickfolk chooses to use 2d10 of hit points then their flame would be extinguished.) If the total hit point dice rolled for burning lifeforce exceeds their total hp then the wickfolk drops below 0 hp and has to start rolling death saves. A wickfolk who has been downed by using their burning lifeforce can be stabilized if someone or something relights their wick.  

If a wickfolk's flame is extinguished and they're still conscious they can use their action to relight their wick; a torch, or spell that deals fire damage can also be used to relight their wick.
An attack made against a wickfolk that involves fire damage relights an extinguished wick, or if the wick is still burning the wickfolk gain 1 use of Burning lifeforce without the use of a hit dice.
Wickfolk are vulnerable to fire damage.
Wickfolk produce a dim light in a 10-foot radius centered on themselves. 

Discuss with your DM about balancing out Wickfolk's abilities.

Increases chosen ability score by 1