So in the world lore for the Forbidden Lands, elves seem to be able to do a lot of things vis-a-vis their gems that there are no rules for.
Shed their flesh
Reclaim a body, on their own, from their gem
Be restored from their gem
Why is this the case? I'd like elves to work as described in the legends and lore as I can't find anything to indicate that the elves of modern FL are somehow 'diminished'. Have I missed something?
I'm not saying the above should be easy for a PC, but I think they should be achievable.
As some people have mentioned already, the lore on elves as described in the Gamemaster's Guide suggests that things that take a lot of time, from the perspective of other kin, are normal for the immortal kin.
Because of that, in my campaign I also assume that some of the elves' special abilities simply take years, decades or even centuries to fully execute. So, for gameplay and balance purposes in my campaign, the list of abilities listed for elves in the Player's Handbook is precisely what a player character of that kin can expect to do in regular campaign time.
If for some elves, "songs that have taken less than two hundred years to compose are not worth listening to" (Gamemaster's Guide), a few decades is surely an adequate amount of time for regrowing a body.