User blog comment:B214/Volume 17 spoilers./@comment-16281343-20140223102732

A question was asked "i can not understand, Does it means that issei will use the Holy Spear to seal Grendel?, or Maybe something more?"

"-Cao Cao himself doesn't appear but his Holy Spear does in order to help DxD out."

And here's nom@n's answer "The Holy Spear just appeared to break the barrier. No one wields it. It was just an instance."