The meeting of Aniruddha and Ūṣā, which caused a great fight between Lord Kṛṣṇa and Lord Śiva, is very mysterious and interesting. Mahārāja Parīkṣit was eager to hear the whole story from Śukadeva Gosvāmī, and thus Śukadeva narrated it.
The meeting of Aniruddha and Usa, who was Banasura's very beautiful daughter, caused a great fight between Lord Krsna and Lord Siva
SB Cantos 10.14 to 12 (Translations Only)
King Parīkṣit said: The best of the Yadus married Bāṇāsura's daughter, Ūṣā, and as a result a great, fearsome battle occurred between Lord Hari and Lord Śaṅkara. Please explain everything about this incident, O most powerful of mystics.
Other Books by Srila Prabhupada
Krsna, The Supreme Personality of Godhead
News of the fighting spread all over the universe. Demigods such as Lord Brahmā, from higher planetary systems, along with great sages and saintly persons, Siddhas, Cāraṇas and Gandharvas—all being very curious to see the fight between Lord Śiva and Lord Kṛṣṇa and their assistants—hovered over the battlefield in their airplanes. Lord Śiva is called Bhūta-nātha because he is assisted by various types of powerful ghosts and denizens of the inferno—Bhūtas, Pretas, Pramathas, Guhyakas, Ḍākinīs, Piśācas, Kuṣmāṇḍas, Vetālas, Vināyakas and Brahma-rākṣasas. (Of all kinds of ghosts, the Brahma-rākṣasas are very powerful. They are brāhmaṇas who after death have entered the ghostly species of life.)
Śukadeva Gosvāmī assured King Parīkṣit that the narration of the fight between Lord Śiva and Lord Kṛṣṇa is not at all inauspicious, like ordinary fights. On the contrary, if one remembers in the morning the narration of this fight between Lord Kṛṣṇa and Lord Śiva and takes pleasure in the victory of Lord Kṛṣṇa, he will never experience defeat anywhere in his struggle of life.