And also What exactly is the role of Brahma, Vishnu and Mahesh in earth and Creation?
According to the Vishnu Purana, the 10 Avatars are the Avatars of Vishnu. It means that the Divine comes down pressing upon the aspect of Vishnu Bhagwan. This is so because Vishnu Bhagwan is the preserver who restores the cosmic order. But if you read the Bhagawat Purana which is regarded as the most authentic scripture, all Avatars including Sri Krishna come out of the Supreme Being and it is His Supreme Divine Personality that first gives rise to the three modes of Brahma, Vishnu, Mahesh which in turn originate the three modes of Nature, that is to say, Rajas, Sattwa, Tamas respectively. It is this Supreme Being with 16 parts who takes birth repeatedly as the Avatar. Since one of the purpose of the Avatar is to restore cosmic order, he takes upon the aspect of Vishnu when he comes. For example, if a father is called by his daughter in case of danger, he will put on the aspect of a warrior and go. But if she calls him in case of sickness, he will go as a healer.
Affectionately,
Alok Da
