Cronus is moving quickly to solidify his position by taking a wife to be his queen. He selects Rhea, but as all the titans are the children of Gaia and Uranus, this is his sister. The Greek family tree was hopelessly tangled in such close family relations.
We meet Themis here for the first time. Of all the titans, she will be the most familiar to most modern people in their everyday lives. Every time you see lady justice, with her scales and blindfol in a court of law, that is Themis. She has a really bad feeling about all this and knows that the future of the titans isn’t going to be all roses and garden parties. She warns them, but the others lack her wisdom and foresight.