Galatea II is formed out of clay, therefore could be immortal. She is not a goddess, but she is most likely the nymph of the stars, sun and moon.
Pygmalion is Galatea's builder, as Aphrodite and Isis were competing against each other to see who was better at dealing with love as Pygmalion has fallen in love with his very own creation. With the help of Athena, Aphrodite turned Galatea II into life, and Pyg declared Aphrodite the best dealer of love. Isis was very sad of that, so Aphrodite declared that they were both the dealers of love. After that, Galatea II and Pygmalion have never been happier.
Galatea II loves to be human and is loved by Pygmalion. She knows the beauty she possesses and is proud of it, but does not boast it out loud.