As soon as the demigods heard and tested the claim of the demon Ascalor, they all scrambled to attack the dark god. They wanted to be the one to kill the dark god as part of its divinity will surely get shed if they tear its body apart.
The dark god felt enraged that these mere demigods look at it as prey. The dark god could only curse the gods of Pandemonium that sealed its power. The dark god wanted to break the seal now but the attack of the archdemon made it lose most of the power that it gathered.
The dark god also got cut off from its dimension all of a sudden which is why it got slower to accumulate its power. The connection with its divine realm is cut off which is why the dark god had to use the power that it had seeped into the fallen imperial capital.
"Whoever brings down the most heads will become my envoy!" The dark god, Nyarlathotep, shouted to all the candidates that are waiting just outside of the imperial capital.