The Emperor had DNA. Perhaps gene-seed was a poor choice in syntax but being derived directly from the genetic makeup of the Emperor himself by decree of Malcador doesn't sound too farfetched. The Tau are inspired by far eastern civilizations. The caste system in particular may be inspired by that found in India but much is also taken from the other civilizations in the region.
But it was stupid to begin with to reason that GK could be immune to Chaos cuz Emperor Gene-Seed lol. Although it's even more awkward to imagine GKs could be Space Wolves (theoretically) DNA is a complete other matter on which I may be ready to agree on
They were never immune to Chaos because of their Gene-Seed. They were immune to Chaos because they're 1 in a trillion, powerful Psykers who have been indoctrinated to the point of madness. The Aegis and massive psychic wards probably help too.
Yeah and Ward added a lil detail that the seed also may hint at it And the super indoctrination is kinda retard because then why not do it with the regular Astartes? And btw. I am teasing you because I dislike the GK
Nah, it's fine. But the main reason why they can't to it with regular Astartes is this indoctrination is so intense that only 1/1,000,000 candidates survive all the necessary trials and rites (Psychic indoctrination is, as one might expect a lot more complex than standard indoctrination.) They literally took the seemingly unbreakable will of an Astartes and pushed them so hard that they broke, the survivors would become Grey Knights.
