User blog comment:B214/Question and Answers/@comment-24098614-20131229091531/@comment-1359322-20131229092506

No one said you can't have your sister as your servant. Riser just has Ravel as his Bishop, it's not like he does anything to Ravel. He even make sure Ravel doesn't fight in his Rating Games matches. The only reason why Riser put Ravel into his peerage is because he wants his peerage to reflect the harem most people desire.

Hell Riser isn't the only one with this issue, Sirzechs and Serafall has way more severe issues over their sisters than Riser. -_-