There is one truth of the world and it is that, no matter how difficult something is, it can be solved with enough time and resources.
Many people know this, but few can take advantage of this nugget of wisdom. Those few must have all the time in the world to be patient.
Undying godclads have all the time in the world, so they are one of the few who can take advantage of this truth. This is one of the reasons why undying godclads keep advancing despite the high difficulty of their advancement requirements.
The other reason that legendary undying godclads can meet this advancement requirement is that the advancement requirement doesn't require them to kill the illusionist. All they need is to eat some of the flesh of illusionists.
If they can speak to an illusionist and buy the flesh from that illusionist, then they won't need to fight the illusionist in order to meet their advancement requirements.
