Dionysus is the ancient Greek god of wine, wine cups, wineskin, grapes and fertility. He inspires ritual madness, joyful worship, ecstasy, carnivals and celebration. He is sometimes included as one of the twelve Olympians. He was also known as Bacchus, the name adopted by the Romans and the frenzy he induces, bakkheia. In addition to winemaking, he is the patron deity of agriculture and the theater. Hailed as an Asiatic foreigner, he was thought to have had strong ties to the East and to Ethiopia in the South. He was also known as the Liberator, freeing one from one's normal self, by madness, ecstasy or wine. The divine mission of Dionysus was to mingle the music of the aulos and to bring an end to care and worry. Scholars have discussed Dionysus' relationship to the "cult of the souls" and his ability to preside over communication between the living and the dead.
In Greek mythology, Dionysus is made out to be a son of Zeus and the mortal Semele. He is described as being womanly or "man-womanish." The retinue of Dionysus was called the thiasus and was chiefly comprised of maenads and satyrs. Dionysus is a god of mystery religious rites. One of the most famous mystery religions was the Eleuinian Mysteries, in which Dionysus may have had a minor role. In the Thracian Mysteries, he wears the bassaris or fox-skin, symbolizing new life. His own rites, the Dionysian Mysteries, practiced by maenads ad others, were the most secret of all. Many scholars believe that Dionysus is a syncretism of a local Greek nature deity and a more powerful god from Thrace or Phrygia such as Sabazios or Zalmoxis.
The garland and the pinecone thyrsus are Dionysus' traditional symbols while the colorful pattern on his entire body can be interpreted in two ways. The first one is the body paint which symbolizes the revelry of Bacchanalia (wine festival). The other thing that links to that body paint is the colorful patterns of all kinds of alcohol when magnified under a microscope.
Shin Megami Tensei III: Nocturne
"The Greek god of wine and orgies. He had two births. When his mother died while pregnant with him, Zeus took the premature infant and let him mature to proper birth in his thigh."
"The Greek god of wine and theater. He had two births. He was originally a god of life protecting the mountains of Thrace. He taught humans how to make wine."
—Shin Megami Tensei: Strange Journey compendium
Dionysus is a demon that can only be acquired through fusion accidents which can be helped along with a Sub App that makes Fusion Accidents occur with 100% certainty, developed after the Black Box retrieval IIEX Mission. He can be acquired easier through taking advantage of the Zealot Summons Sub App.
Dionysus makes an NPC appearance in Sector Bootes who initiates the EX Mission, Death distilled. He asks the protagonist to retrieve a feather from a Zhen to mix into a poisonous wine. Despite the wine's nature he claims that, as a god, he cannot be affected by such wine and desires a taste. After retrieving a Zhen feather, Dionysus remarks lamentably that he cannot share such wine with the protagonist and goes off to find a suitable meal to compliment the newly made wine.
Shin Megami Tensei IV
A demon faced in the Challenge Quest "The Great Drunkeness," given by Nozomi. Dionysus is found in the Ginza Shopping District. Surprised that a man was intrigued by his wine, he offers his fellow oenophilist a chance to drink it in exchange for his life. Defeating him earns the Maenad's Wine for the quest.
After being defeated, he can be summoned through a special fusion of Naga, Mayahuel and Dantalian in the Cathedral of Shadows. He can teach Flynn the Purple Smoke and Doping skills through his Demon Whisper.
Devil Survivor 2 Record Breaker
"The Greek god of wine and theater. He was fervently worshipped by female mystery cults. He was originally a god of life protecting the mountains of Thrace. He taught humans how to make wine."
—Devil Survivor 2 Record Breaker compendium
Dionysius is one of the first demons contracted by the party at the start of the Triangulum Arc of the game, the others being Sarasvati and Bai Suzhen. He is now the lowest-leveled and earliest-available member of the Omega race in the game.