Subthalamotomy is not reversible because the brain cells are permanently killed.
He can be permanently killed only with a wooden implement.
Presumably, if I got permanently killed, that would be the same as giving up, and the remainder of my predestined route would be voided.
Immortal characters could thus be killed permanently without beheading, and when decapitated do not release the Quickening.
As in WC, some wingmen can be killed permanently in combat.
However, they can only be killed permanently by either exposing them to direct sunlight or stuffing their severed heads with garlic.
In theory a daemon whose physical body is destroyed in the presence of the Blank would be permanently killed.
For a few months, one type of "Star Wars" character, the rare and powerful Jedi, could be permanently killed.
These generals can be permanently killed during certain scenarios, although the player can opt to save them should he/she wish to do so.
Because of this immortality, he can never be permanently killed.