Four Crystal Emperors

It was written in the ancient text that there were four Luminary Crystals in the whole universe. This crystal was a power reactor or an energy plant. Mostly the same as the monster orb of a monster. But if a person placed the monster orb of a monster lord and the luminary crystal together, anyone would pick the luminary crystal.

It's twenty times more effective than the monster orb of a monster lord. It could also hold much more energy and the output it could release was much higher. That's why the people who were chosen by luminary crystal were powerful. They were known as the Four Crystal Emperors.

The 1st one was from the emperor of the Red Crystal Empire.

The 2nd one was from the Jade Emperor of the Heavenly Palace.

The 3rd one was a rogue god from the Ruin Desolate Continent.

The 4th one Dark Emperor Zargon.