User blog comment:Zathronas/Analysis by an author: Volume 2 episode 8: Field Trip/@comment-10390252-20140926134640

I'll say this much: We don't have Zwei's full story yet. I've got a feeling that it is somehow associated with Ruby's repeated Beowolf motif on her clothing and in her thoughts. Could Zwei be a genetically-modified Beowolf that is being tested to see its suitability as a pet/guard-Grimm?