Not all exposition needs to be handled in dialog. Some of the smaller details can be left as very subtle clues. Readers who find and understand these hints will feel clever, and those who don’t probably won’t miss them. For instance, the S on Stabby’s shirt is supposed to look as if is was made from crudely smeared blood stains. Two separate stains, as if they were created after two different stabbings. Stabbings that held special significance.
In panel three, I mention that Stabby’s parents were found stabbed, but I’m sure that’s just a coincidence.