Dionysus, the god of wine, had a dual nature. Like the moods brought on by the fermented grape drink, he could be turn from divine ecstasy to brutal rage.
Like many Greek gods, he had a peculiar birth. When Zeus, in an invisible form, made his mortal mother Semele pregnant, Hera god wind of it, and sought revenge by causing Zeus to show himself to her. This was too much for the mortal woman, and she was burned to death by the sight of his glory.
However, Zeus managed to rescue the unborn Dionysus, and stitched him into his thigh until he reached full term, in the bargain conferring immortality on his half-mortal son.
Hera, still jealous, made another attempt on the life of Dionysus by arranging for him to be killed by the Titans. However, Rhea rescued him and he survived to grow up. Later, he went to the underworld to find his dead mother Semele, and was able to overcome Thanatos and bring her back alive to Mount Olympus. This was a highly unusual feat.
Dionysus was the subject of a spring festival that involved theatrical productions. Most of the classic Greek dramas written by famous ancient Greek playwrights including Sophocles, Euripides, Aeschylus and Aristophanes were created to celebrate the Dionysian feast.