Tortured Feline Demon.

He spent all his wealth to hire helpers. He communicated with people to see if he could buy world fragments to equip his weaker helpers. He did all of this while hoping that his realm didn't have a realm lord or his invasion would be doomed.

What Monarch High Heaven did to the 500 million Origin gods wasn't fair. In the past, he was a realm lord with a Supreme law and the power of the world behind him, but even he had to prepare for many Origin cycles, craft 10 billion world fragments, employ 500 billion immortals and demons to fight for him before he started the era of conquest. But he isn't giving any of the 500 million Origin gods time to do any of that.