The comprehensive picture drawn here of Vyasa in the MBh includes his functions as seer, priest, ascetic, and spiritual preceptor. Of all the epic’s, Vyasa is the one who most closely corresponds to the idea of brahminhood promulgated by the dharma literature and the MBh’s Shanti Parvan - The section of the epic having the greater similarity to the dharma literature.
Vyasa is depicted as the spiritual preceptor of five Brahmins who learned from him the Vedas and the Mbh, and whom he instructed in religion . He also gave spiritual counsel to members of the Bharat family, both Pandavas and Kauravas , exercising control over their lives. That he was their spiritual preceptor as well as their concerned elder is particularly evident in the case of Pandavas, in whose lives the major events were supervised by Vyasa.
In the religious traditions of the Hindus, the most important author of sacred texts is Krishna Dvaipayana Vyasa. He is traditionally credited with the arrangement of the Veda into four texts as well as the composition of the epic Mahbharata (Mbh), many Puranas, and other works. Vyasa, however, has been described as mythical as his existence is impossible to prove except in myths and legends such as are preserved in the epic.
Various inscriptions refer to the Mbh (Mahabharata) as the composition of Vyasa, the Veda divider, the son of Parasara, and as containing 100,000 verses...
Although the Mbh is the text having the most information about Vyasa, there are few references to him in Sanskrit literature that predated the Mbh or is atleast contemporaneous with the early phase.