The Underworld King fell silent.
Naturally, he did not dare. The immortals regarded the Underworld as a filthy place, yet they would neither conquer nor occupy it. The immortals needed the Underworld tribe to properly manage the reincarnation passage; that passage was the main artery, while the Immortal Realm and the Mortal Realm were minor paths opened up later, sharing the resources of reincarnation.
Furthermore, the Underworld was inherently formed from the dark and negative aspects of the immortals. These vile things were shunned by the immortals, who feared contamination and could never return to them.
Chapter 1700