This is just plain stupid. So this whole prison arc is pointless in the scope of the main plot. I thought it was some artifact that could help him in the battle but it's just a dragon egg, now hatched and went Adios. Vikir just wasted nearly three years, letting the demons grow stronger and open the gate. All for the sake of this supposedly 'far future guardian'. He could've killed the remaining demons first, while they were still weak, and then did this hatching.

Honestly, this whole Nouvelle Vague arc is making me lose interest. 2 years passed before he faked his escape and now more months faking out as a guard. Don't see how not going after the demons directly is less efficient than getting this Poseidon while giving the demons time to grow stronger and wreak havoc. Within his one year at school, he took out No.5 to 9. Even if No.2,3,4 are colluding, I'm not convinced this is the best approach.