With the release of issue 172 it is pretty evident now that Carl and Sophia are going to be the ones that end up together. The series seems to be on the trajectory of going on the (yes cliched) route of boy and girl grew up together. Girl begins to like boy as they get older but boy is interested in a hotter girl and stops giving the girl he grew up with the time of day. Boy eventually comes around and realizes how much the girl he grew up with means to him.
So in order for that to happen the role Lydia is playing needs to go away and how do you see that happening. You think she will get killed off within the next couple arcs or do you think she will simply break up with Carl permanently?