I wrote Emma to be Fred's enemy from the get-go. Fred detests those who harm vulnerable people whereas Emma targets the vulnerable (well as well as "sinners") As Fred's brother is openly gay, he's accepting of people regardless of sexuality whereas Emma because she deems gay people as "sinners" will kill them. Fred has a zero-tolerance policy when it comes to harming children (hence why he developed anger problems when chasing Mary Graham) whereas Emma isn't afraid to cross that line if the kids are "weak" or "sinful"