In Hindu mythology, an astra was a supernatural weapon, presided over by a specific deity. To summon or use an astra required knowledge of a specific incantation/invocation, when armed. The deity invoked would then endow the weapon, making it impossible to counter through regular means. Specific conditions existed involving the usage of astras, the violation of which could be fatal. Because of the power involved, the knowledge involving an astra was passed from a teacher to a pupil by word of mouth alone, and only following the establishment of the student's character. Certain astras had to be handed down from the deity involved directly, knowledge of the incantation being insufficient.
Astras come into importance mainly in the Ramayana and Mahabharata, where they are used in the great battles described in each epic. They are depicted as used by archers such as Rama, Lakshman, Meghnad, Karna, Bheeshma etc. The astras were generally invoked into arrows, although they could potentially be used with anything—Ashwatthama invoked an astra using a blade of grass as his weapon.
The following are astras mentioned in the Ramayana and Mahabharata:
| Astra | Deity | Effect |
|---|---|---|
| Indraastra | Indra, god of weather | Would bring about a 'shower' of arrows from the sky. |
| Agniastra | Agni, god of fire | The weapon discharged would emit flames inextinguishable through normal means. |
| Varunaastra | Varuna, god of water | The weapon discharged would release torrential volumes of water. This weapon is commonly mentioned as used to counter the Agneyastra. |
| bhargavastra | bhrugu, clan to which Parashuram belonged | Parashuram gave this astra to Karna. It caused great damage to Pandavas army. |
| Nagaastra | The Nagas | The weapon would have an inerring aim and take on the form of a snake, proving deadly upon impact. |
| Nagapaasha | The Nagas | Upon impact, this weapon would bind the target in coils of living venomous snakes.(in the Ramayana, it was used against Lord Rama and Lakshmana by Indrajit) |
| Vayvayaastra | Vayu, god of wind | Bring about a gale capable of lifting armies off the ground. |
| Suryastra | Surya, god of the sun | Create a dazzling light that would dispel any darkness about. |
| Vajra | Indra, god of weather | Target would be struck with bolts of lightning (vajra referring to Indra's thunderbolt). |
| Mohini | Mohini, an Avatar of Vishnu | Dispel any form of maya or sorcery in the vicinity. |
| Twashtar | Twashtri, the heavenly builder | When used against a group of opponents (such as an army), would cause them to mistake each other for enemies and fight each other. |
| Sammohana/Pramohana | Would cause entire hosts/armies to collapse in a trance. | |
| Parvataastra | Would cause a Parvata/mountain to fall on the target from the skies. | |
| Brahmaastra | Brahma, the Creator | Would destroy entire hosts at once. Could also counter most other astras. |
| Brahmasirsha | Brahma, the Creator | Capable of killing devas. Was used by Ashwatthama on Parikshit. It is thought that the Brahmasirsha is the evolution of the Brahmastra |
| Narayanaastra | Vishnu, the Preserver | Would create showers of arrows and discs. The astra's power would increase with the resistance offered to it. This weapon had to be obtained from Vishnu directly, and could be used only once. If the user were to attempt invoking it a second time, it would rebound on him, and possibly, his troops. |
| Vaishnavaastra | Vishnu, the Preserver | Would destroy target completely, irrespective of target's nature. Infallible. This weapon had to be obtained from Vishnu directly. |
| Pashupatastra | Shiva, the Destroyer | Would destroy target completely, irrespective of target's nature. Infallible. This weapon had to be obtained from Shiva directly. |
1. "The Ramayana" 2. "The Mahabharata" 3. "Bhagavata Purana"