Now, mika is turning into a black demon, I think yuu will learn his lesson. Specially, after all the things Guren's done to all of 'em-He 'betrayed' his comrades and killed many of them back in nagoya while again experimenting on seraph of the end. According to ferid, he's the one who destroyed the world.And more importanly, yuu saw THAT guren's been doing humen experimentation underground. But Still, yuu kept believing Guren. Now, guren's killed mika, who knows what yuu will do?
Believe guren or not?
(Just shared my thought)
To share the glory of the anime, the wiki has articles to detail character experiences in that format! So few series ever get anime, and the incredible Seraph of the End one brings the characters to life in a different manner, with all their experiences documented along with the manga version of events on this all covering encyclopedia!