I think everything should have a slayer to which it is weak. Whether that means cramming more monsters into existing slayer groups or adding new ones, I don't care. I just want every creature to have a slayer type. I think sea serpents would be perfectly fine in the reptile group. In fact, when I first started here and was fishing I tried using a reptilian death weapon on them thinking it would work on them. Also, the loch lake monster should have a slayer!