Bruh there's like 5 more kinds of "undying" beings you either haven't mentioned or just loosely grouped, maybe more depending how exactly we interpret it. I really don't like your super regeneration, because this can apply to most kinds of undying beings.
As I said before, those were the only four in my head at the time.
I focused more in general archetypes.
Liches can move their souls to other undead bodies (this is similar to your parasite, but the mechanism is completely different).
The ones I know will die if their phylactery is destroyed.
Reincarnators are arguably undying as well, though this can be debatable; if we're talking about undying MCs though, then it should count.
Fair enough.
Gods or spirits in some settings are beings of faith that do not die so long as people believe in them; they may regenerate, reform, or be reborn as a new entity.
Some beings like spirits or gods may possess a body or an avatar, death of which doesn't affect them.
Some elementals, slimes, and many more beings remain alive so long as at least a singular building block remains, and they can reform or regenerate with time or other resources (this is where most regenerators end up).
All these are conditional immortality.
Some supernatural beings are fundamentally neither alive nor dead, such that they inherently cannot die.
If we're talking conceptual entities or beings that reside beyond the mortal plane of existence, yeah.
My favorite overall is that last one, but for a main character I would choose various kinds of regeneration.
Regeneration all the way.
I like the undefined body archetype. Slimes, or water elementals. Maybe even an eldritch horror shapeshifter. They can functionally always reassemble, no matter how they are obliterated.
Though, from those three I personally am closest inclined to water elementals, or in my turn on them, water angels, as they wield powers on a far greater level, capable of creating the greatest constructs of water.
Don't these types use up energy to regenerate?
Though if I go by the same logic then the healing factor archetype too would be nerfed.
Players may count as possessing a body/avatar, depending on how specific we want to be.
Creating a list like this is kind of stupid because on one hand you have to make some generalizations so you don't end up with thirty barely different categories, but if you try to compress them, you'll frequently have to lump distinctly different things together. How much is appropriate mainly depends on whether we're focused on the mechanism or function. OP didn't specify and did both.
Like I said, I was just stating the general archetypes, this wasn't even an attempt to create a list.
Maybe the villain in the movie Fallen?
Or maybe, one of my favorites, the man known in life is Firoun Al'Faisel (or something close to that), but who, until an experiment turned his domain from Darkon to Necropolis, was known better by a corruption of his title, A'Za-lan (Warrior/Mage/King) - Azalin the Lich. As long as his phylactery remained intact, his essence would transfer to the nearest corpse within his domain and transform it into an exact copy of his body.
Haven't seen fallen, but from a brief wiki search, the villain, Azazel(right?), also possesses others, which would be badass if they they weren't able to identify a possessed individual through Syrian Aramaic
