UngeheuerLich
Legend
Why? It makes you immune to some spells, but makes you weak against others. That's it.I'd rather it not be, just because I feel it should have a higher "power budget".
And while we are at it, I'd add half-orc, or half-elf human feats.
Origin feat is the right place because do you want to be an ordinary elf or human for 3 levels with background farmer just to notice you are actually fey/half-elf or half-orc?
Compare it to the magic initiate dip, or musician, not to something like crafter.