Learning the cultivation stages in the Immortal Realm left Yun Huaxia, Lu Yi, Jin Shiyan, Bai Qiyin, Bai Lili, and Lu Er dumbfounded. Like the rest of the mortals, they treated all people in the Upper Realm as Gods and Goddesses with immortal life. Only now they had understood that even in the Upper Realm there is a measure of strength like in the Mortal Realm.
The requirements to increase strength and cultivation stage were harsher than the ones from their realm. Like divinity, purity of bloodline, and things like that. Mortals weren't usually born with special and strong bloodlines like the other races. They have ordinary bloodlines and they have weaker physiques than the other races.