The Serpent is male, the verse refers to him as "he"
Viper I would guess is genderless unless the picture is distinctly that of a male viper, not being a herpetologist I wouldn't know.
Saint of Virtue is a bit of a tougher case. The verse/title gives no clue and the art could be classified as androgynous or male, so I would guess at genderless atm.