I'm curious about how powerful Lidusis will be if Blow succeeds in awakening him.
The way I see it, Blow is now a mixture of the original Rood Sentia with aspects of the personality of the Demon King. This includes a sizeable fraction of his power, but if Lispen and Rubymonter are right, the greater part of that power is within Lidusis.
We also know that Lidusis can, and has used a fraction of the power Lispen hid within him before, even though that might have not been conscious. I'm talking about slaying the demon that killed Ibriel and almost using it in Ishuella.
Then again, the demons (Lispen, Dio) say any human who happens to lodge that power will eventually die from it, either in the process of having it extracted or by being consumed by it. Lispen even told that to Duke Artian in that flashback a few chapters ago.
However, Rood seems confident that it's not a done deal that Lidusis will die. However, demons are supposed to understand magic much better than humans (since it originally belonged to them exclusively), so anything that is beyond their ken should have to do with aspects of magic that are peculiar to humans' use of it.
Namely, awakening. The plan to awaken Lidusis must have been conceived of by Rood after talking with Meredith.
But we readers have never seen a first awakening of a magician. We only know a few things:
i. A magician becomes marked with a symbol somewhere in their body.
ii. They receive a name (possibly of their own choosing, but nobody is sure).
iii. They acquire something of a demonic nature.
iv. Their class seems to be intrinsic to their nature. So Rood and Shic were first class magicians from the very beginning. Training can improve your skill, but won't make your raw power any greater.
v. There isn't strong evidence for that, but Awakening seems to be dangerous. The teacher who welcomed Rood into the school said many magic students lose their minds. Frustrated magicians seem to be able to counterfeit/steal marks (that was said in one of the early school chapters, too).
vi. Kiel has told Blow (if that's what the translation implied) it's not easy to restrain a training student (when they awaken, I assume). So awakening may also be dangerous to other people besides the magician who is undergoing it. This seems to imply that wannabe magicians need… guidance, protection? from established magicians during awakening. (Kiel probably guided Rood, and Lanoste must have guided Shic.)
Perhaps that's why Blow thinks he can stabilise Lidusis' awakening - since he is a class one magician with a little of the king's power. That's not something Lispen, Dio and Rubymonter, who had nothing to do with humans before coming to their world, would know.
Now I'm thinking that Blow may not be able to do it alone. Cue Shicmuon, the only magician other than Meredith whose power rivals Blow's, to lend a hand (in exchange for Blow agreeing to fight him to his heart's content).
And if Lidusis awakens with the king's power… Mikelcarugo will have an epic death! o/