User blog comment:B214/Volume 23 discussion blog/@comment-31137559-20170413122356/@comment-31137559-20170413145638

Diehauser's Worthlessness makes special traits and special ablilities Worthless. Issei's Penetrate ability can allow him to break through barriers. There's a difference. And he wouldn't need to know about the evil pieces themselves, but the ability of the evil piece to render it worthless. Wouldn't be that hard for him considering he's the first monster from the House of Belial and is most likely the first to master that ability to such a degree.