Indra is the king of the gods and ruler of the heavens. Indra is the god of thunder and rain and a great warrior, a symbol of courage and strength. Vayu is his friend and servant and the Vasus are his advisers. Indra’s mount is the elephant Airavata and he also has a golden chariot drawn by ten thousand horses.
Indra is as quick as the wind and carries a hook, sword, conch, noose, a rainbow and the much feared magic weapon Vaijra. His kingdom is situated near Mt. Meru and Indra’s love for Amrita (Soma) is legendary.
At many times, Indra lost controll over the heavens to the demons. So Indra became always watchful to destroy any man or demon that became too powerful. In the Life of Ganga epic, Indra saw King Sagar triumph over all kings of the Earth. When King Sagar decided to organize an Ashwamedh Yagya (horse sacrifice) that would make him emperor of earth, Indra stole the horse and hid it with Sage Kapila, who later burned Sagar’s army to ashes.
As Bhagwan Krishna himself made a discoure in geeta, showing the glory of Indra;
वेदानां सामवेदोऽस्मि देवानामस्मि वासवः ।
इन्द्रियाणां मनश्चास्मि भूतानामस्मि चेतना ॥
Indra is, with Varuna and Mitra, one of the Ādityas, the chief gods of the Rigveda (besides Agni and the others such as the Ashvins). He delights in drinking Soma, and the central Vedic myth is his heroic defeat of Vṛtrá, liberating the rivers, or alternatively, his smashing of the Vala cave, a stone enclosure where the Panis had imprisoned the cows that are habitually identified with Ushas, the dawn(s). He is the god of war, smashing the stone fortresses of the Dasyu, but he is also is invoked by combatants on both sides in the Battle of the Ten Kings. He is married to Shachi or Indrani, and is the father of Arjuna (by Kunti), Jayanta, Midhusa, Nilambara, Khamla, Rbhus, Rsabha. Indra is a brother to Surya. He is attended to by the Maruts (and the Vasus), children of Diti (mother of demons), and Rudra. Indra had slain Diti’s previous wicked children, so she hoped her son would be more powerful than him and kept herself pregnant for a century, practicing magic to aid her fetal son. When Indra discovered this, he threw a thunderbolt at her and shattered the fetus into 7 or 49 parts; each part regenerated into a complete individual, and the parts grew into the Marutgana, a group of storm gods, and assisstance of Indra.