Galinthia is a lizard-like giantess who, on the eve of Jason's coronation, attacks a group of travelers on their way to Corinth for the event. She holds a grudge against the royal family because, ten years earlier, she was attacked by King Aeson. When she resurfaces after being unheard from all those years, Balian advises Jason to capture and execute her. The prince tries to reason with her first, which goes almost-predictably horribly and results in Galinthia being captured after all. She escapes (mostly thanks to Hercules taking pity on her) and takes Iolaus as a hostage, saying she'll kill him if Jason doesn't give up his own life.
It is revealed that, at one point in her life, Galinthia was a human. In fact, she was the midwife who aided Alcmene when Hercules was born. Because of this role she played in Hercules' birth, Hera turned Galinthia into the giantess she is now. Upon realizing who Hercules is and remembering the kindness Alcmene showed to her when she was human, Galinthia agrees not only to spare Iolaus and Jason's lives, but to leave Corinth as well.
- According to Ovid's account of Hercules' birth, Alcmene did have a servant by the name of Galinthias. When Hera tried to delay Hercules' birth by getting Eileithyia (the goddess of childbirth) to sit with her hands clasped and legs crossed, Galinthias told the goddess that Hercules had been born anyway without the goddess' influence. The goddess was so startled that she jumped up and unclasped her hands, which finally allowed Alcmene to give birth to her son. Angered by the deception and by Galinthias' mocking her for being so easily fooled, Lucina changed her into a weasel.