Mercy is a mermaid from Xanth. She was introduced in Jumper Cable.
Mercy served Prince Charming for 10 years after rescuing him, however, he married someone else. After his wife died, he wanted to marry Mercy, but she would not marry him and wanted to return to the sea.
Human men and women will not have a species in their entries. Also, if the surname of the character is the character's species, it was dropped.
If the character is a child, it will be in the description. The child will more than likely be an adult by this time in the Xanth series.
Many species are single gender, so their entries will not mention it. The species are Fury, Muse, basilisk, cenmaid, cenmare, cockatrice, dryad, maenad, sand witch, sandman, and woodwife. Harpies and nymphs are usually female, and fauns are usually male; but there have been a few exceptions that are noted.
In some instances, I have made educated guesses on gender, species, and some birth years.