The Katar is an armed spacecraft representing India during the battle against the invading Nazis. It is designed to look like the Katara, a traditional Indian dagger.
It's main weapon is unknown, and it was not seen firing at all.
The Katar was later destroyed when the Götterdämmerung collided with it.
The filmmakers designed the Katar by combining two fan-made designs, one which had the Katara shape and another with the 'Peacock tail' solar arrays.