Board Thread:Questions and Answers/@comment-93.87.198.81-20151226152246/@comment-33177490-20160206235021

Yu was able to receive a lot of power up from not only his Seraph Mode alone, but he have been transformed into a complete demon unlike Guren, a Namanari who is still part human and part demon. By the way, that would also mean taking a pill of drugs to do so.

Out of all the members in Shinoa's squad, it's either between Yu or Mika that holds the most power within the group because they're more than just a Seraph.