The supreme beings represent the pinnacle of existence. Even though Pei Xuanjing is only a cultivator of the eighth realm, his power is such that other cultivators cannot help but respect him.
Those who are also supreme beings like the Blood Fiend Ancestor can choose to incarnate themselves to pay a visit, but for other cultivators to descend in their spirit form could be considered disrespectful towards Pei Xuanjing.
For demonic big shots like the Blood Fiend Ancestor, in the past, suppression of an incarnation would not be a big deal, causing no harm to their essence. They simply need some time to recover.
However, the important consideration now is actually for the many subordinates and disciples who have followed them here. These cultivators of the seventh and eighth level of the Spirit Realm may not be the entirety of their power, but a loss would be unacceptable, especially in this critical juncture.
