Indra is the King of the Gods in early Hinduism, analogous in many ways to Zeus in Greek mythology, or Odin in Norse. He is the god of the weather, as well as the god of war, and is personified heavily in the mythology of Hinduism. He is a character given over to displays of love and bravery, and drives many of the greatest romantic tales and tales of valor.
Indra is usually described visually as having red skin and four arms, and is usually depicted wielding the lightning bolt weapon, Vajra. He was born to Prthivi and Dyaus Pita, the Earth and the Sky, and is sometimes said to be the twin of the god of fire, Agni. Like Agni, he is said to have been born in full strength, ready for battle. He married the goddess Indrani, and by her had many children, including Midhusa, Nilambara, Rsabha, Sitragupta, Rbhus, Arjuna, and Jayanta.
In battle Indra was unparalleled. He defended both mortals and the gods from the forces of evil, riding into battle on his mount, the enormous four-tusked white elephant Airavata. His weapon, the Vajra, was able to cut through any substance, divine or otherwise, acting as a spear, a mace, and a sword.
The most famous of Indra’s great battles for man’s benefit was his battle with the dragon Vritra. In his greed, Vritra had hoarded all of the water of the earth, allowing none to drink of it. The people of the earth were unable to battle Vritra, and so were stuck in a constant state of drought. At last, Indra was born, and his first great task was to liberate water from Vritra. He consumed a great deal of Soma, the power-granting drink of the gods, to become incredibly powerful. He battled his way through ninety-nine fortresses, finally coming to Vritra. They battled in the sky, evenly matched in power, none besting the other. In the midst of the battle, Indra reached above the clouds and retrieved the thunderbolt, Vajra. With it, he struck one great blow against Vritra, bursting his stomach wide open, and freeing all of the waters of the earth that were held within.
Indra was ultimately somewhat displaced by the Trimurti of Vishnu, Brahma, and Shiva, when Hinduism changed to worship these three gods above the others. In this later period, Indra was portrayed as somewhat weak, and the tale of his battle with Vritra actually ends with him needing the help of both Vishnu and Shiva to destroy the dragon. He was eventually placed as lord of the minor gods of the pantheon, but still subject to the rule of the greater gods. This is best demonstrated in tales in which Krishna repeatedly shows himself to be immune to Indra’s power.
Many of Indra’s tales, like many Greek tales, demonstrate a basic moral lesson. One famous tale of Indra, Indra and the Ants, is a simple lesson in temperance. After rising to be King of the Gods, Indra asks Vishvakarma, the builder of the gods, to make him a mighty palace. He keeps asking for more and more to be added to the palace. Overwhelmed, Vishvakarma asks for the help of Brahma, who asks for Vishnu to help. Vishnu goes to the palace in the form of a small boy, and admires the palace, saying it is even better than palaces made by the former Indras. Indra laughs at this, but then the boy continues to talk about the past Indras, all eventually destroyed and reborn in the infinite cycle of death and rebirth that claims the entire universe. Humbled, Indra leaves the palace and becomes a hermit. Eventually, Indra is shown that running from the world is no way to live in it, and learns to balance a worldly existence with a spiritually awakened one.