Zagreus.
      Zagreus (Ζαγρεύς = "the god of pitfalls"? following M.L. West) in ancient cult had a roll in Orphism, but a less clearly articulated role in mainstream mythology. The myth of Dionysus' dismemberment was apparently a unspeakable feature of Eleusinian and Orphic mystery religions. Consequently, the divinity has very little presence in the classical tradition of reception and adaptation.

      Zagreus is son of Zeus and Persephone and known as "the chthonic Dionysus". Destined, as offspring of Zeus, to succeed the sky-god, Zagreus' rise was thwarted by Hera's jealousy and the Titans she tasked to kill the infant. The Titans dismembered and consumed the child's body, except the heart which Athena recovered still beating. According to Orphic theology, Semele conceived "the second Dionysus" either after she ingested Zagreus heart herself or after Zeus ingested the heart and then impregnated Semele. Olympian Dionysus, thus, is a resurrected divinity, one who experienced a second begetting from Zeus; but, Dionysus-Zagreus is the manifestation of the divinity begotten in the world of the dead and killed there by Titans.

— RTM


Further Reading:
Burkert, Walter. 1985. Greek Religion. Harvard University Press. Fauth, W. RE, s.v. "Zagreus", IX A 221-83. Simon, E. 1966. " " Antike Kunst 9:78-86. Gordon, Richard L. Brill's New Pauly s.v. “Zagreus” — http://dx.doi.org/10.1163/1574-9347_bnp_e12214290.


See also:
      Dionysus
      Semele
      Titans and Giants