The Eminence in Shadow, Vol. 11 (manga)

"Upon arriving at the Oriana kingdom, Cid is broadsided by the news that Princess Rose is set to wed Duke Perv--an unexpected development that would throw a major wrench in his future shadowbroker plans! Seems like it'd be a good idea to crash the party and get the deets, but are there even bigger schemes at work behind this unholy matrimony?"--Provided by publisher.