I always thought shiranui was like a shadow and i was right but i though she was zenkichis shadow which turned out she was medakas , well she was neccecary for zenkichi since he cant do anything with medaka . Its like zenichi married madeka on only in paper but his real wife who conforts him is siranui ( probably lik a mistress ) , after this arc zenkichi may notice that real one he loves is actually shiranui not medaka
( i hope so )