An arahant. During the Akkhakkhāyika famine, Dutthagāmanī provided him and four others with a dish of sour millet gruel, which was purchased with the proceeds of the sale of the king's earrings (Mhv.xxxii.30). Mahādeva took his portion to Sumanakūta and shared it with nine hundred others (Mhv.xxxii.49). He was also among the eight arahants who accepted a meal of pork from Sāliya in his previous birth as a blacksmith (MT.606). He was probably so called because he lived at Kotapabbata in the Malaya country. MT.606 he is called Kotapabbatavāsika.
It is said that for three years after his ordination Mahādeva lived in the Maindalārāmaka vihāra (Mahādeva called Maliyadeva in the context (AA.i.22), but further on in the same passage (p.23) he is addressed as Mahādeva). One day, while going for alms in Kallagāma, near by, he was invited by an upāsikā to her dwelling, where she gave him a meal, and, regarding him as a son, invited him to take all his meals at her home. The invitation was accepted, and each day, after the meal, he would return thanks with the words "May you be happy and free from sorrow" (sukham hotu, dukkhā mucca). At the end of the rainy season he became an arahant, and the chief incumbent of the Vihāra entrusted him with the task of preaching to the assembled people on the Pavārana Day. The young novices informed the upāsikā that her "son" would preach that day, but she, thinking they were making fun of her, said that not everyone could preach. But they persuaded her to go to the vihāra, and, when the turn of Maliyadeva came, he preached all through the night. At dawn he stopped, and the upāsikā became a sotāpanna.
Maliyadeva once preached the Cha Chakka Sutta in the Lohāpāsāda, and sixty monks, who listened to him, became arahants. He also preached the same sutta in the Mahāmandapa, in the Mahāvihāra, at Cetīyapabbata, at Sākyavamsa vihāra, at Kutāli vihāra, at Antara-sobbha, Mutingana, Vātakapabbata, Pācīnagharaka, Dīghavāpī, Lokandara, and Gamendavāla, and, at each place, sixty monks attained arahantship. At Cittalapabbata he saw a monk of over sixty preparing to bathe at Kuruvakatittha, and asked permission to bathe him. The Elder, discovering from his conversation that he was Maliyadeva, agreed to let him do so, though, he said, no one had ever touched his body during sixty years. Later in the day, the Elder begged Maliyadeva to preach to him, and this he did. Sixty monks, all over sixty, were among the audience, and at the conclusion of the Cha Chakka Sutta they all became arahants. The same thing happened at Tissamahāvihāra, Kalyāni vihāra, Nāgamahāvihara, Kalacchagāma, and at other places, sixty in all (MA.ii.1024f).
Malaya Mahādeva was among those various large groups who renounced the world in the company of the Bodhisatta: the Kuddālasamāgama, Mūgapakkha samāgama, Cūlasutasoma samāgama, Ayogharapandita samāgama and Hatthipāla samāgama (J.iv.490; also vi.30, where Mahāmaliyadeva is called Kālavelavāsī). It is said (Vsm.241) that two monks once asked Malaya Mahādeva for a subject of meditation, and that he gave them the formula of the thirty two parts of the body. Though versed in the three Nikāyas, the monks could not become sotāpannas until they had recited the formula for a period of four months.