Replicating what Monarch High Heaven did won't be easy if only for the fact that they have already used up their Authority of the Void Universe. It is still lacking compared to what the realm lord used since they had used 18,648, not 10 billion units of Authority.
By their estimate, he had gained a Supreme power of 10,000 from his array of world fragments. That is far away from where they are currently.
Even if they combine the boost from the Crown of Domination with their world fragment, the best they will get is 3 × 12 Supreme power. 36 is nowhere near 10,000.
But while they don't have 10 billion world fragments, they have something much better. That something is a foundation that is capable of growth.
That foundation is their incomplete universal artifact. It can still grow into a Universal artifact. All it will take is some divinity and their Supreme law.
