I don't know this is intenssional or not... but...
Being Rad poison drops max health... kinda like DS2 when dying.... more of it will bring the player's max health further down... Ghouls are people who sere exposed to Rad too much and too long... now "Cursed" with deformaty, and awaits their Hollow...I mean going feral...
SO...
When you recieved Rad poison, you are "Hollowing" and as you get futhur Rad poison... you get less and less max health Darksouls2 style... but this one have no limit,,, and when you die by Rad... you become Fera (Full Hollow)
MIND BLOWN!~
totally should make:
*long white beared Ghoul Blacksmith "...and be careful out there.. nither of us want to see you go Feral..."
*when die by Rad poison... player character should display transformation animation to a Feral Ghoul...