The heartland of the Fiend Domain.
Apart from black and earth-grade sects that fought everywhere for resources and territories, there were also some heaven-grade sects and factions lingering in this area.
At the level of heaven-grade sects, there would definitely be Grotto-heaven experts presiding over the sect—those were Fiend Kings!
This area of Zephyr Thunder Palace was under the jurisdiction of Black Fiend Sect.
Unlike the Nine Firmament Immortal Domain, generally speaking, no matter how many sects and factions below fought one another, even if one of them was destroyed, Black Fiend Sect would not interfere.
As the Sect Master of Black Fiend Sect and a Fiend King, Fiendcelestial Black Heaven had seen too many sects and factions rise and fall and was long used to it.
In his opinion, the only way to nurture true paragons for his use was through continuous killing and conquest!