This artifact must be very powerful. Fortunately, they are not without resources for them. They have a world engine, a world spark, some fragmented knowledge of Supreme laws, and a supply of cosmic energy. They have to do something great with these things or they will disappoint the first sage and let down his generosity to them.
Legion aims to build this artifact with these items. They will use Soverick's expertise at weapon forging, the tree father's ability to transmute energy to create the artifact, Legion-7's manipulation of the laws, and the immense mental power of all of Legion to create it.
It will be a very powerful artifact and a source of power that will be with them forever. In the meantime, the world is not going to wait for them. Things are moving fast throughout the realm. Power is changing hands and wars are being waged. Even the demons and the abyss are being affected.
AETERNUS'S POV
Demons are strange creatures. They are weird but they are also unique in that they are present in every realm. Every realm tree has an abyss where demons live so demons are a race that is common throughout the void universe. Their purpose is to create strife for each plane and push them toward greatness through violence.
The abyss is a feature of the universe in every realm tree. Each realm tree has a different abyss attached to it. But what happens to the abyss when the realm tree detaches itself from the law matrix of the universe after the era of conquest?
The purpose of demons is understood. So is their source. What will become of them after the era of conquest is also known. The abyss will disappear. A plane will be created for them if the realm lord is willing to have them. If the realm lord isn't willing to have them then there will be no place for demons in the realm anymore.
Demons will become fugitives in the realm without the abyss. Sin energy will die off when the abyss disappears so demons won't be able to regenerate energy anymore. This won't affect demon nobles and above but it will affect the entire demon race.
The lower-ranked demons will die off and the absence of the abyss will also prevent the creation of new demons so the entire demon race will eventually become history. This is known with certainty. So what are demons to do if they want to avoid that future? The answer is that they don't care and nothing will be done.
Powerful demons know what will happen if the abyss is lost but they don't care. Demon nobles and above don't need sin energy anymore. They can live on mana and that is enough for them. They don't care about the other demons or what's going to happen to them. The ones that care are the weak high-rank demons and below who need sin energy but they can't do anything to change the situation.
How are high-rank demons to make enough contribution to the era of the conquest and make the realm lord owe them a favor? High-rank demons are equivalent to mid-gods or lords of law at most. They won't be of much use in a battlefield full of immortal Origin gods. Their fates might as well be sealed. They have to become stronger and become demon nobles before the era of conquest ends.
It is fortunate that demons will have much bigger problems if the realm actually loses the era of conquest. High-rank demons won't have to worry about sin energy because every demon will die except demon kings and above. The defeat of the realm tree is a much more serious situation. Even the demon kings and demon gods that survive won't even have the luxury of becoming fugitives in the realm because there will be no realm.
If not for this unpalatable situation that will occur if the realm tree were to lose in the era of conquest, then nothing would be done about the fate of Demons and no demon will care about the outcome of the era of conquest. Demons are just too selfish to care about the fate of others including their entire race.
Powerful demons began looking towards their own situation. Demon lords are hoping to perform enough during the era of conquest so that the realm lord can make them demon kings. His Will can substitute for that of the abyss and make them demon kings of the realm.
They will be like demon kings of the abyss in that they won't be able to progress beyond that rank but it is still good. Any progress is good. Half-bread is better than none. For a lot of demon lords that have had their path blocked by a demon god, this is the opportunity they have been waiting for.
As for demon kings. They want to become demon gods. Demon kings of the abyss are stuck where they are. Their fate is intertwined with the abyss. They can't make any progress and they can't survive if the abyss is destroyed. So they must help the realm tree survive and they must make enough contribution to its victory so that the realm lord will keep the first plane of the abyss.
The other type of demon kings don't have to help the realm tree. They can survive even if the abyss and the realm tree are destroyed. They will only lose the opportunity to progress. On the other hand, if they help the realm lord, they will have a shot at reaching the pinnacle of their existence and become demon gods.
Then there are demon gods. They are the pinnacle of the race of demons. The next step for them is to become Chaos entities. The chances of that happening will become very slim to almost impossible if the abyss is lost. So demon gods decided to involve themselves in the preparation of the era of conquest. The already chaotic situation in the realm became more chaotic.