Here is a terrible placeholder post where I left the bad spelling in becasue it amused me.
This is based on Zedeks post here - and Richards comment about 'Partibility' not being a part of the D&D background CulturePool.
So here are some ideas for magical, 'Epic Level' heroes. The GodFighting types, and what happens to them if they die or if they just get sliced to bits, either by a Deamon or as part of a Glorious Sacrifice that Saves the World... Or just becasue they fucked up.
A book - probably, and a magic animal, like a familiar.
Probably the book and the familiar have different intentions and try to influence their owners to do opposing things. "You have to stop this thing from happening/no you have to MAKE it happen!"
Probably all high Wizzards become frustrating dementia-addled horcruxes on their death and the old spells hang around like feral pets.
An ever-burning fire, of RAAAAGE! / A magic Shield - maybe thats more Paladin.
A throne of SKULLS.
A majic sword obviously.
Or a loyal yet magic hound like Jake in Adventure Time or that one in the Silmariliiion.
The dog thing and loyal-but-basic-but-still cool animal friend theme would work well here.
Most of the more-practical warrior stuff would fit in well here. What happened to the soul of my 11th-level fighter? Oh a gods wearing him as a suit of armour now.
What I think of more as I play this is that it would be a good idea for a 'Primal' First-Age or Age of Heroes or even Neolithic or Biblical-style game. You could play a game in one of those eras in 5e, but with a low technology level. Then once all the characters die heroically fighting the gods, move to an early modern era with LotFP, so the low power level and grimness of the rules matches the 'fallen world' feel. Everyone feels weaker and less heroic. And the magic thingys the PCs have to find, and even the landscape they have to traverse, is made from their dead heroes from the previous game.
I can imagine a fighter so basic and brutal that one part of them is transformed into a hammer, for the maiming of nerds, and behold, their seperate part is ALSO a hammer, to do exactly the same thing - smash nerd face.
A sneaky dimensional portal, one end is hidden and you have to be clever to find it, the other end keeps moving about but its usually in a rich guys bank vault, or somewhere else people don't want you to go.
A flock of creepy birds, like Rooks or Crows.
A secret interdimensional place, like a Tardis or that Harry Potter station.
A fast ship.
Oh god I just re-invented the Black Peal - NO.
A mask maybe? Or a lie? A particular lie that only exists because of this particular thief, and wherever the lie is, the spirit of the thief is also.
A fountain or something that heals the pure.
I feel like this has already been covered by well, every religion pretty much.
It would pretty much depend what god they were into. Something like a huge waterfall might work.
An ever-boiling storm or cyclone for the heavy-metal gods.
An ever-healing bush for the hippy gods.
Widsom fruit for the knowledge gods.
A big valley full of angry animals like dinosaurs because they were so badass when they died the world just crrraccked open and SAVAGERY came out.
Or a really ANGRY horse that is a mount for a god.
Or a fucking insane mountain with snow on top where you can SHOUT AT THE GODS.
Maybe the strength of a Barbarian could become a whole herd of MASSIVE animals like Buffalo, and the spirit could become a harsh north wind or something.
Snow and Biting Wind would be an appropriately Northern-Esque result.
Oh god, I suppose a merry chuckling river or a cheeky monkey or something.
OR an ever-playing viola that can irritate the mildest heart.
Or a foolish dog.
Or maybe a pleasant forest where the 'music' is the wind in its branches?
Or a fucking BIRD.
I'm thinking sombre protective ghost/magic defensive shield.
Like a Hornburg-style last-fortress. A last-defence-against-evil situation.
An eerie flat lake with strange shadows and possibly a sword-dispensing lady in it.
A Paladin turning into a magic lady and a sword on being bisected feels strangely right. The lady to carry the sword around myteriously, bestowing it on people and then turning up to take it back.
Or a promise. That would be an odd one. Whenever you swear in a certain way or on a certain idea, phrase or object, they are there somehow, incarnated in the oath, and the oath is only possible because of them.
No forests on Flat Earth Wake UP.
Also maybe a big animal or a whole forest.
Really a druid should just retuuurn to naaaature. Probably become a breeze or grass or something.
Or literally turning into a stone circle, with each stone being a bone, or a place they dropped their blood, like Thors last-three-steps.
Shit, do you just become pure Chi-Force?
Oh you could actually become a punch, like a literal dragon-punch or Iron-Fist thing where now a new move exists in this reality and any time someone does this particular punch it CANNOT BE BLOCKED except by a defence thing that is also you.
So your chi (aptly enough) seperates into this perfect Yin/Yang thing, accessed through a particular martial form, which can only be countered by its other half. Which might be in the posession of your adopted brother who KILLED YOUR SENSAI.
A Ranger is a hard one really. Less basic than a fighter but not as froofy as a Druid.
Probably something like a route, a safe journey that connects places and keeps travellers protected.
One part of Strider became the only safe path through the SkullFuck mountains, the other became the trading winds that carry us over the Awesome Sea.
A messanger figure would work as well, like a long-flying bird belonging to a God.
Anyone wanking off to Chthulu is going to get eaten by Chthulu. The only thing they should leave behind is a path of temptation and certain DOOM. Like a True Detective mystery or a rumour of perverse and uncontrolable power. The ruins and remains of each Warlock and Sorcerer provide the path of damnation for the next. So maybe the mystery itself is what is left behind, like a pervy Dan brown book. Embedded into the substance of reality itself, something that pulls you into a Ligotti Story.