I got this idea from another game that made a unique health system for a character, “masks”.
Byron is a character with low health and a certain amount of masks. Every few seconds, his health becomes the proportion of current divided by total masks (5). (If he has no masks health just works normally) Whenever he takes damage (while his health isn’t restoring its state), he loses a mask. Hence he becomes this guy who you want to kill really quickly otherwise he just ups his health, or just shoot him five times while waiting a few seconds for his mask mechanic to settle down.
Example for anyone confused: you hit him and he goes down to four masks. Let’s say you get him all the way down to 1hp and his max up was 10,000. That’s great, but then his unique gimmick might trigger and get him back to 8,000 health.
At the same time, your allies have difficulty healing byron since if you bring him back to 10k his gimmick will trigger him back to 8k in a few seconds. It’s a double sided ability, which may be controversial. You can balance it if you feel the double edge is unfair.
Bronze, soulless shot: gains armor and shield proportional to masks lost and charged for a powerful shot. Loses a mask after using this ability.
Silver, deathless grasp: hits an opponent and limits their max damage to a certain amount.
Gold, breathless smoke: whenever Byron loses a mask he becomes invisible for a certain time
Platinum, soul trap: if Byron kills someone, he regains a mask and all allies regenerate health. This can only be done once per battle.