I hope it does not come as a shock that Dionysos has a complex and often confusing family tree. I’ve divided this into three tales:
Standard myth: has him the son of Zeus and Semele, daughter of the founder of Thebes, Cadmus (his grandfather) and Harmonia (his grandmother). If we look back through Cadmus’ family tree Zeus is something like Dionysos’ great, great, great, great grandfather via Io. Zeus is also his great grandfather on Dionysos’ grandmother’s family side. And as a technicality Zeus is his father and mother… is your mind twisted yet?
If we regard Orphic mythology: the Olympian Dionysos is a second incarnation. His first incarnation is known as Zagreus-Dionysos, the son of Persephone and Zeus.
Zagreus is a supreme deity that Zeus concedes the throne to his son, thus giving Zagreus the universe as a mere babe. As is typical in myth: Hera is jealous, and employs the Titans to kill Zagreus. The Titans play with the child with toys, eventually presenting Zagreus with a mirror. The reflected splendour of Zagreus entrances the god himself, giving the Titians an opportunity to pounce on him; killing the child and eating him.
Upon smelling the foul odour of his son being cooked Zeus discovers the crime of the Titans and smites them to ashes (From which humanity rise from the ashes, part evil Titan and part divine Zagreus-Dionysos). Zeus saves the essence of Dionysos (his heart, soul or phallus) and impregnates Semele, therefore giving birth to Dionysos we know now.
If we want it take it further into the odd we can look at speculated myth: (What follows should not be treated as acceptable myth. There a few ancient sources to supports this, but not in a linear fashion I present it.)
In vague references Zagreus is the second incarnation, the last being the third. The first and most pure is Phanes, the first god of the cosmos. Zeus either eats Phanes or engages in cosmic fulicio… (that is not a joke) …. whatever the case, Zeus absorbs the supremacy of Phanes and passes this to his children. In some cases this can be Dionysos and Athena. (Thereby making them divine twins?)
This is source of Zagreus’ supremacy. Continue on with the the myth above.
These tales of back and forth death and rebirth, “refinement”, are typically regarded as the farming of vine and the process required to create drinkable wine. (As already mentioned in previous posts).