Dionysus was the god of wine and theater. He was the only
one of the twelve Olympians that had a mortal mother. Her
name was Semele, but she died before Dionysus's birth. How
is this possible? Well, since Zeus happened to be there
when Semele burst into flames(it was his fault after all),
he was able to save Dionysus while he was still in Semele's
womb by taking him and sewing him into the skin of his leg.
When the proper time for Dionysus's birth came about, he
sprang from his father's leg as a newborn god. Since he
had been born from Zeus's leg and not from Semele herself,
he was not a demigod although his mother wasn't immortal.
He grew up with tigers and leopards for playmates, hidden
from his stepmother Hera. When Dionysus was fully grown
he went up to Mount Olympus and assumed his place as one
of the twelve Olympian gods. He was able to do this only
because Hestia, who had previously been one of the twelve,
gave up her seat so that Dionysus could have it. His followers
were the satyrs and the wild maenads.