A small quandary with 10A, "Does a Glaucus, to start with, perhaps qualify as one?" S?A?O? If the first 6 letters of the clue make the answer, I construe SEAGOD. But on second thought, you could perhaps call him a SEADOG as well. Which solution is preferable (unless it is a third thing entirely)? TIA!
Thank you mamyalynne and scorpiojo, I will go with the majority! (I was thinking of the rescuing sailors bit for SEADOG, but it isn't his most basic quality).