Mortal-tier son of Castor by Hilaeira the Leucippid. The Castor-Hilaeira / Polydeuces-Phoebe pairing of the Dioscuri-Leucippides marriages produced the only attested Dioscuri offspring per Apollodorus 3.11.2 and Pausanias 2.22.5. Mortal-tier registration reflects Castor's Tyndareus-paternal mortal-share of the Dioscuri pair (compared with Polydeuces's Zeus-paternal immortal-share); his half-brother Mnesileos (by Pollux) is quartigod-tier through the Zeus-paternal line.