Indra , his elder son, who throws him out of the sky to fall to death (RV 4.18.12). Thomas Oberlies tentatively identifies Dyaus with an asura in pre-vedic religion, who was also slain by Indra . But the hypothesis remains largely unsupported. Note all the "D" emanating everywhere. and Devas http://en.wikipedia.org/wiki/Deva_(Hinduism