Darkness is actually Fujiwara Yusuke. Fujiwara speaks of the magnificence of the World of Darkness, but Fubuki opposes his thinking. Fujiwara activates the field magic Clear World, conferring a Negative Effect on Fubuki. On top of this, he summons a high level clear monster, Clear Vise Dragon. Clear Vise Dragon is a monster which increases it's fellow monsters' offensive abilities two-fold. Fubuki finds himself in a dire situation. And, unrelenting in his attacks, Fujiwara shows Fubuki the darkness in the hearts of Majoume, Asuka, Shou and the others.
Then, no matter what monster you 
send out, you can't surpass it.