Dionysus (Διόνυσος in Ancient Greek) is the god of wine, and the son of Semele and Zeus. He is also known as Mr. D, the Camp Halfblood camp director. Dionysus is not only the god of wine, but also the god of ritual, parties, madness, as well as the 'cult of souls' because he looked over the communication between the living and the dead. He is never called Dionysus by the Romans. He is instead called Bacchus or Liber.
Dionysus was often called the 'twice born' because of some of the myths around his birth. The most common is that his mother was a mortal woman named Semele, who was a daughter of the King of Thebes, and his father was Zeus.
As with most of Zeus' acts of infidelity, Hera became jealous when she found out that Semele was pregnant with Zeus' child. She disguised herself as a nurse (or old crone in some stories) and made Semele begin to doubt that it was truly Zeus. While in disguise; Hera convinced Semele to ask Zeus to reveal his true form, to make sure that he would do it, and to swear on the River Styx; which is sacred to the Greek Gods and an unbreakable oath. Zeus tried to get around the promise, but in the end swore on the River, and Semele asked to see his true form. Unable to go back on the promise, he did so, and she was burned to ash.
Zeus managed to save the infant, sewing him into his thigh until he was born a few months later as a full grown baby on Mount Pramnos in Ikaria. He was born a demigod, like Hercules and Perseus.
In his early life Zeus sent Dionysus off with Hermes. Again here, there are two versions of the story. In one version, Hermes took Dionysus to King Athamas and his wife Ino, who was Dionysus' Aunt. Hermes had them raise Dionysus as a girl to hide him from Hera's scorn. The second story is that the boy was taken to the rain nymphs of Nysa. They raised him through infancy and childhood, and in reward for their care, Zeus placed them as the Hyades in the stars. The main idea was to hide the child from Hera's continuing wrath.
When he grew up, he discovered the vine, and extracted the juice. He was struck with madness by Hera at this point, and ended up wandering various parts of the world. Rhea cured him, and taught him her religious rites, and he wandered through Asia teaching about cultivating the vine.
He was very handsome as a young man, eager for challenges. Dionysus later said he was good at nothing in his human life but cultivating wine. The people in his village mocked him, not knowing of his heritage, of his father, or knowing his future, and what he would one day become.
When Dionysus was invited late to the Mount Olympus, it was Hestia who graciously offered him her golden chair to prevent any conflict or embarrassment. Hestia was a goddess known for her warmth and kindness.
Dionysus then rescued his mother from Hades, and she became a goddess on Mount Olympus, with the new name Thyone, presiding over the frenzy inspired by her son Dionysus.
When Theseus abandoned Ariadne sleeping on Naxos, Dionysus found and married her. When she died, he went to the Underworld and rescued her, taking her up to Mount Olympus, where he made her immortal.
He was disguised as a mortal on the seashore once, and a few sailors spotted him.They thought he was a prince, and tried to kidnap him and hold him for ransom or to sell into slavery. They tried to tie him up, but no ropes would hold him. Some ideas are that the material they were made of then was similar to the vines, and would refuse to hold him. At this point Dionysus turned into a lion and let a bear loose on board. It killed those it came in contact with, and those who jumped off the ship were turned into dolphins as an act of mercy. The only one to survive was the helmsman Acoetes, who had recognized him as a god, and tried to stop his comrades from the beginning.
After chasing after an off-limits wood nymph twice, Zeus punished him by putting him in charge of Camp Halfblood for 100 years. During this time, he is not allowed to drink wine or grow wine grapes.
Dionysus has a chubby face, curly hair, and usually bloodshot eyes from drinking. He is usually described as wearing tiger-striped Hawaiian shirts and purple running shoes. Anyone can tell he's no stranger to wine just by looking at him.
His hatred for heroes stems back to how Theseus abandonedAriadne, and thus is why he has the fewest demigod children amongst the major gods (Excluding the Virgin Artemis and the oath bound Hades, Poseidon and Zeus, maybe)
Dionysus lets it be known he cares nothing for the campers, and does not ever show any fondness towards them, though he dislikes Tantalus (who had been treating the campers badly), finds humor in his attempts to grab food, and is happy to send him back to the Fields of Punishment. He is no kinder to Chiron, but never threatens him like he threatens the campers and he likes a good party.
Dionysus's powers are based around plant growth with a strong focus on products of the vine. He can quickly summon multiple vines strong enough to ensnare, strangle, and even break his enemies into pieces or encourage more benevolent growth. It is unknown to what degree he can control the growth of plants not based on vines. He also is able to apparently transform anything into wine, as he stated at one point "The next person, or horse, who calls me the "wine dude" is going to end up in a bottle of Merlot." He can also induce or cure madness.
As the god of madness, he can easily cure and ease madness, he has the standard powers of a god, including levitation, teleportation, conjuring items and transforming people, as well as incinerating them.
Dionysus can change his appearance and turn into his Roman counterpart, Bacchus. As Bacchus, he becomes more disciplined, warlike, and militaristic. Since gods can appear at multiple places at once, Bacchus might be camp director over the Roman camp while Dionysus is over the Greek camp and he might be the exact opposite of Mr. D's persona there since the Roman camp is supposed to be more disciplined.
Dionysus is the god of wine and insanity. These children do not experience dyslexia and ADHD like other demigods, being able to sort out things in their minds very well. They can control the vines of grapes and strawberries, and make them grown in the most peculiar places. They can make wine and other alcohols with no problem, and theirs is always the sweetest. Dionysus's children never get drunk, and alcohol poisoning is a totally foreign idea to them. They are also able to cause confusion in the mortals around them.