| I grok do u |
The only way I found was the third Evangelist (fiendish) boon for Apollyon.
There is a corruption that removes immunity, but no way for a PC to inflict that.
I thought a plagued curse oracle could use oracle's burden, but the curse doesn't remove disease immunity unlike the toxic blood curse does with poison immunity.
| Azothath |
sometimes supernatural diseases bypass certain restrictions, then there's infestations.
you might want to focus on curses rather than diseases or poisons. Technically afflictions.
Retraining is your friend.