"Many hundreds and thousands of demons, demi-demons, Yaksas, Raksasas [man-eaters] and others, headed by Sumali and Mali, resisted the armies of King Indra, which even death personified cannot easily overcome. Among the demons were Namuci, Sambara, Anarva, Dvimurdha, Rsabha, Asura, Hayagriva, Sankusira, Vipracitti, Ayomukha, Puloma, Vrsaparva, Praheti, Heti and Utkala. Roaring tumultuously and fearlessly like lions, these invincible demons, all dressed in golden ornaments, gave pain to the demigods with weapons like clubs, bludgeons, arrows, barbed darts, mallets and lances."

Srimad-Bhagavatam 6:10:19-22

"Thereafter, two very powerful demons named Mali and Sumali were killed by the Supreme Lord, who severed their heads with His disc. Then Malyavan, another demon, attacked the Lord. With his sharp club, the demon, who was roaring like a lion, attacked Garuda, the lord of the birds, who are born from eggs. But the Supreme Personality of Godhead, the original person, used His disc to cut off the head of that enemy also."

Srimad-Bhagavatam 8:10:57

Bhaktivedanta Book Trust. Excerpted from texts and purports of HDG A.C. Bhaktivedanta Swami Srila Prabhupada.

The story of Vishnu’s fight with the Rakshasas, led by Malyavan, Mali and Sumali, is also narrated in the Uttarkanda of the Ramayana (Cantoes VI-VIII). The story is as follows:

There was a powerful Rakshasa, called Sukesa, who was a great favourite of Siva. Sukesa had three sons called Malyavan, Mali and Sumali. Proud of the boons they received from Brahma and Siva, they became insolent and began to harass the demigods. To seek redress, the latter came to Siva and sought his refuge. Because of his soft feelings towards Sukesa, Siva expressed his inability to take any stern action against his (Sukesa’s) sons and directed them (the demigods) to go to Vishnu to seek his protection.

The demigods, as directed by Siva, came to Vishnu eulogised his greatness and sought his protection against the atrocities of Malayavan, Mali and Sumali and their Rakshasa followers. Vishnu, pleased with the prayers of the demigods, assured them that he would soon make short work of the Rakshasas. The demigods then left for their respective abodes.

Having come to know of Vishnu’s assurance to the demigods, Malyavan, Mali and Sumali flew into rage and summoned their forces to attack the demigods. The Rakshasa troops moved under Mali’s leadership. Informed of the movement of the Rakshasas, Vishnu also became ready to fight with them. He put on his celestial armour shining like the sun, equipped him-self with a pair of quivers full of arrows and also his other weapons, the conch, the discus, the mace, the sarnga bow and the sword. And then mounting on his beautifully feathered vehicle, the Garuda, he set out to destroy the Rakshasas.

A grim battle ensued between Vishnu and the Rakshasas. With the blast of his wings, Garuda shook the army of the ogres, brought down their banners and displaced their weapons. The Rakshasas in their hundreds surrounded Narayana-Vishnu and afflicted him with volleys of missiles. To foil their efforts, Vishnu discharged sharp arrows on them from his Sarnga bow whose strings he pulled to the extreme length.

Dispersing the Rakshasas by his arrows, Vishnu blew his great conch Panchajanya, the sound of which shook the three worlds and struck terror into the heart of the Rakshasas. Pierced by Vishnu’s darts, the Rakshasas fell in hundreds and thousands on the battlefield. The sound of the Panchajanya and the twang of his bow drowned the cries of the Rakshasas. At the end, Vishnu cut off the head of Mali with his chakra. Seized with fear, Malyavan and Sumali, with the remnants of their forces fled towards Lanka.