Crius is the Titan personification of leadership and heavenly constellations. He is a son of Uranus and Gaia. He is married to Eurybia, who is the daughter of Gaia and Pontus. In this sense, Crius is the first Titan to not marry his own sister, as Eurybia is his half-sister. Some progress, but we take every win we can find. His example would not be followed by many other Titans and Gods later on.
Crius and Eurybia conceived three children together. The first was Pallas, the Titan personification of warfare. He would later befriend Athena, but it might have been better to avoid that. The second is Astraeus, the Titan personification of the dusk. He would later marry Eos as the Titanide personification of dawn. Finally, there was Perses, the personification of destruction, draught, and fires.