Dionysus
Young god. Son of Zeus (king of the gods), and the mortal woman Semele. Also called Bacchus, Bromius, or Evius. Dionysus should not be thought of as the merry god of wine; this concept of him is part Roman, part Disney. The Greek deity was much more complex. Wine was only one of Dionysus' gifts to mankind; he is also the god of excess, savagery, ecstasy. Eurpides uses him as the embodiment of all that we fear: the irrational, the savage, the exotic, the Other. But he is of a dual nature, both foreign and Greek, child of both mortal and god, male but effeminate; his nature therefore is part of our own. Teiresias warns Pentheus that Dionysus is god of wine, dance, revelry, wildness, and war; he is also the god who mediates between the other gods and mankind.
He is simultaneously an abstract force and an anthropomorphized deity. He has been traveling in Asia, teaching his mysteries to mankind, and now he has returned to Thebes to initiate the land of his birth into the new religion. He has also returned for revenge: when his mother Semele died in a blaze of lightning, Semele's sisters said that Zeus was punishing her for saying she had been his bride. Semele's sisters called the dead woman a liar, and they denied the divinity of Semele's baby; the child, Semele's sisters assumed, must have died with Semele. But that child was Dionysus, and he has returned now to establish himself as a god.
Chorus of Asian Bacchae
Not to be confused with the Maenads. The Maenads are the women of Thebes, possessed by Dionysus, who run through the wilderness of Cithaeron performing miracles through the power of the god. The Bacchae are followers of Dionysus who have come with him from Asia. They are not possessed, and so their will is their own. But they are fervent believers in the god. In the end, however, even they pity the victims of Dionysus. The god's revenge is too harsh, and the Bacchae look on Agave and Cadmus with compassion.
Coryphaeus
The Chorus leader. She speaks for the Bacchae at key points; it is she who tells Cadmus that she pities him, and at that point she implicitly speaks for the other Bacchantes as well.
Teiresias
Blind old seer of Thebes, familiar to those who have seen/read Oedipus the King or Antigone. According to myth, he was immortal and blessed with the power of prophecy. While Sophocles makes Teiresias an awesome presence, nothing less than the mouthpiece of the gods, Euripides makes him vulnerable, almost pathetic. In Sophocles Teiresias stands as a window into the will of the gods; he is a sign that there is an absolute truth to which man can refer. In Euripides, the seer's vulnerability reflects the uncertainty and complexity of the cosmos. The will of the gods, if it exists at all, is both capricious and inaccessible to man.
Cadmus
Grandfather of Pentheus. Father of Agave. The aged patriarch of the house, he has stepped down and allowed Pentheus to take the throne. Though once a hero of some renown, he is now a fragile old man.
Pentheus
Young boy, king of Thebes. We are told later in the play that Pentheus does not yet have a full beard; that puts his age at no older than his late teens. He is an impatient and impetuous young king, and he rejects the new religion and its god. Some have argued that he symbolizes rationality, but close attention to the play reveals that he is anything but rational. He rejects anything he does not understand, and his greatest crime is his lack of self-knowledge. Dionysus preys easily on the boy's weaknesses, turning the young king into a scapegoat for the crimes of Thebes. But Pentheus' excesses and crimes against the god are understandable. He is only human, and he is only a boy. For these reasons, Dionysus' revenge is brutal and excessive.
Attendant
One of the attendants, a speaking part. He brings Dionysus, captive, to Pentheus.
First Messenger
A herdsman from Cithaeron. He brings the news of the Maenad's supernatural powers and their brutal attacks on the villages in the foothills.
Second Messenger
A slave. He attended Dionysus and Pentheus when the god brought the boy to see the Maenads. He returns with the account of Pentheus' horrible death.
Agave
Daughter of Cadmus. Sister of (the late) Semele. Mother of Pentheus. Because she blasphemed Dionysus when she said Semele was not pregnant with the child of Zeus, she is one of the targets of Dionysus' vengeance. Possessed, she mistakes Pentheus for a wild beast and, with the help of her sisters and the other Maenads, rips Pentheus to pieces with her bare hands. She returns to Thebes, splattered with her son's blood and carrying his head impaled on a stick, believing that she has killed a lion. Cadmus, grief-stricken, speaks with her gently until the madness passes; only then does she look at the thing she carries.
Various attendants
Slaves and soldiers who serve the royal house of Thebes.