From the Diabolical Dragon King's memories, Wu Yu learnt that the two demonic empires were Olden Empire and Perpetual Demonic Empire.

These were two other empires run by a 9-heavens demonic emperor.

The Olden Empire was ruled by Olden Demonic Emperor, whose true form was the Olden Golden Mountain. He was a golden mountain, and very few of them became demon. But through the endless passages of time, enough spiritual qi had awoken its sentience.

It was said that this Olden Demonic Emperor could control all metals, and was above average amongst the five demonic emperors in fighting ability. These demonic emperors all still had potential to mine, and they were far from the end of their lifespan. If things continued this way, they seemed on course to become eternal demon emperors.

The scant resources in Demon Immortal Realm had put the brakes on their progress, but it was still merely a matter of time for Olden Demonic Emperor. 

Such demons had boundless potential, and onen could only imagine how devastated they must have been when they ascended into a broken world. Otherwise, they would...