Deathless Fleshgrafter

Aereni Elf, caster level 5, proficiency in Religion.

You can grow and graft the tissue and body parts of deathless creatures onto others, granting the recipients of your grafts new, potent abilities.   Benefit. You can create and attach any deathless graft whose prerequisites you meet (see the individual graft for the specific requirements).
A character with at least two deathless grafts gains advantage on saves against poison or disease. A character with three grafts gains resistance against poison and disease damage. Once the character receives their fourth graft, they become immune to poisons and diseases altogether, and there are no further bonuses for the fifth graft aside from what abilities the fifth graft gives on its own.