Who is Dionysus a.k.a. Bromius, Evius, Bacchus (from The Bacchae) from Euripides V and what is their importance?

Dionysus is the son of Zeus and Semele, who is human. Hera, enraged by Zeus' infidelity, struck Semele dead with a lightning bolt during childbirth. Zeus, however, saved Dionysus at the last minute. Dionysus is the god of wine and dance.