These groups are those who have been lofty and enjoying endless honor and privilege since the Creation of Heaven and Earth—the innate holy beings, and the various innate races they lead, each possessing a long history and unique heritage!
To them, Taiyi simply wishes to establish a so-called "Demon Clan," opening up a brand-new advancement pathway for those ordinary postnatal spirits. To some extent, this is something they can actually understand, and even acknowledge.
However, the crux of the issue lies in the fact that—you say you wish to use this "Demon Clan" concept to merge the Ten Thousand Races, implementing that so-called idea of "all beings can become demons," ultimately achieving "unification of all races." This has made many innate holy beings, rulers of innate races, and even some top sovereigns who have established their own Great Universe, feel quite… discontent!
