Aeternus is a demon. All of Legion are selfish but Aeternus embodies the ideology of taking whatever they want and destroying whatever they can't have. So if they can't have the world fragment, they might as well use it as kindling to kickstart their world engine. They don't need the first sage's agreement to do that.
The tree father was skeptical about it. He expressed his skepticism, "But it will only work once even if we manage to get it working. We will need several attempts to get our law matrix working perfectly since there might be several problems in the future. A single-use solution is not good enough."
Legion-1 also expressed his thoughts about it. "Plus it will be very dangerous to do it. The first sage will surely not be happy if we tamper with his supreme law. His unhappiness might bring problems for us if he manages to find my location. That is a possibility since we will be using his world fragment within my inner world."
They began to brainstorm how to build a kindling engine that would act as a world engine that would then kickstart the main world engine so that they could use the main world engine to power a law matrix that they would build to transform Legion-1's inner world into a world fragment that can bear the backlash of the law matrix of the universe and help them to use the power shards.
It is quite an overwhelming task that is becoming more complicated as time passes.
Soverick groaned. "It is as they say. Nothing is as simple as it seems."
They have truly underestimated the difficulty and complexity of creating a world fragment without the power of world gods. They knew it was going to be very difficult and he expected some changes along the process to increase that difficulty. They thought they could handle it with the wealth of skills and talent that they had at their disposal. But things are getting more and more complicated for that single goal.
Their confidence was not baseless. After all, there are very few that could match Soverick's forging skills, even fewer that could perform energy transformation as well as the tree father, and practically no one who could match Legion-7 manipulation of cosmic energy at the Origin level.
When these things are combined with Legion-1's inner world and the virtual creation legacy, who wouldn't think they couldn't build a world fragment? Apparently, they were wrong. The distance between an Origin god and a world god is too wide.
But they didn't give up despite the difficulty. They can't give up because the reward is too high to give up on. If they give up and focus on becoming world gods, they will surely be able to build a world fragment as world gods, but it would have no use to them then. It is now that a world fragment will benefit them immensely.
So ideas were traded. Some were shot down while others were raised up and buttressed. The major problem now is how to take advantage of the world fragment of the first sage to kickstart their world engine. Legion has decided to use it as the kindling they need.
This world fragment contains the complete false supreme law of order of the first sage. It is a treasure that neither Soverick nor Legion-7 can use or take advantage of for fear of the first sage's scheme.
For one, they can't even open it or the first sage will get the location of Legion-1's inner world. That is obviously bad. Even if they risk the sage finding out about Legion-1, there is nothing they can use the supreme law for without the first sage's permission. Soverick can't comprehend it without exposing his mind to the first sage. That is something that they must not do unless they are ready to fight the first sage.
This is because there is no way they can avoid gaining the first sage's attention as soon as he comes in contact with the supreme law. The sage will be able to observe him and his location during the process. Even if they manage to circumvent those risks, comprehending too much of the supreme law is courting death in its purest forms. He will literally have the first sage in his mind. That is opening a back door into Legion for the first sage.
A false law of order is not as virulent and insidious as a false law of Chaos. It does not instinctively try to overwrite all of existence but it is capable of it if the owner is willing to do so. The owner is the law itself so to comprehend the law is to have the owner of the law in your mind.
As if that isn't dangerous enough, to comprehend the false law of order of a world god is usually seen as examining them for weaknesses. After all, you are analyzing their existence. It is an act of war which might lead to retaliation. This retaliation will also occur throughout his existence hence why Legion is not willing to risk it.
The supreme law present within the world fragment that the first sage gave them is mostly useless to them because of the danger it brings. Legion-7 can't eat the supreme law either despite his love for devouring laws. The supreme law is too pure and complete. It will completely overwrite Legion-7 if he attempts.
Legion-7 was badly affected when he devoured the serpentine world gods' law. It was pure and it was a little of it and yet he was forced to mutate. If not for cosmic energy helping him to assimilate the law and evolve, then he would have died.
So they have decided to sacrifice the world fragment. But the challenge of taking advantage of the world fragment is not an easy one. They have to come up with a plan that can work, has a high chance of success, and won't endanger them too much.