Oh hey, I was right- Mephistio wouldn't of moved if it weren't for the fact that Iruma swayed him. In regards to the Scala exam, Mephistio was only to watch, not to interfere.
The fact that he's using the flag with his approval- the very approval he said was embarrassing and was trying to get rid of really shows that Mephistio has a good degree of both intelligence and political prowess. I mean, we knew he probably would just because he's listed as the 'Mind-Games' king, but it's a little different then seeing it in action. in a few seconds completely turning around the situation! Of course, with his power too, but he made a clear political stance too.
Mephistio will probably become Iruma's political teacher, and we'll get little flashes to them sitting and discussing stuff like we are with Bachiko right now about the piercing the barrier and such whenever Iruma pulls out a political move!
I do think on Narnia's side, he's clearly showing his own weaknesses. He's very book smart- but not emotionally competent. Or- politically competent. Kalego is the same way. Their family is the guard dogs of the demons- they care naught for politics as stated before.
But 13 crowns is politics. Henri was handling the politics side before while Narnia was beneath him. Probably shielding Narnia from the consequences of his actions and preventing Narnia from fully attacking. Probably, Narnia has always been shielded from the consequences. But he's intellectually smart enough- temporarily allying with demons that dont' want to do what the Three Greats are doing and wanting to undo Delkira's actions. Right now, intellectually, it was smart to cut off Iruma's access to Mephistio. As he said "That thing upsets the balance of the Demon World. Proof of this is the unnaturally large amount of power that has gathered around him. Sullivan, Asmodeus, Barbatos, and other powerful demons."
It'll be interesting to see if Narnia will learn from this, or not. The knee jerk response is that he won't, but demons are crafty. I can see him realizing that baring his fangs any further will bring about negative consequences. But I can also see the other way around. We might not see the consequences of this for another 100 Chapters. We're still waiting to see Toth's number as a diety come around, from way back in the harvest festival. Nishi and Oda both seem pretty good about circling back to older statements and plot points (though, admittedly, some can be lost. We're all only human)