There is a legend that twenty-eight Vyasa’s existed before the present Vyasa Rishi, more commonly known as Veda Vyasa. Vyasa whose birth name is Krishna Dvaipayana took birth at the end of Dvapara Yuga. Krishna Dvaipayana was born of Parashar Rishi through the Matryakanya Satyavathi Devi. Parashar was a great sage and astrologer. Parashar learned that a child conceived at a particular time would be born as the most remarkable man of the age, an Ansh of Lord Vishnu Himself. On that specific day, Parashar was traveling in a boat, and he told the boatman; that an auspicious time was nearing. The boatman had a daughter who was of age and awaiting marriage. He was impressed with the greatness of the Rishi and offered his daughter in marriage to Parashara.
Vyasa was born of this union, and his birth is said to be due to the blessing of Lord Shiva himself, who blessed the union of a sage with the highest order Janani although of a low caste. According to Vishnu Purana, Vyasa was born on a river island of the Yamuna at Kalpi.
Vyasa turned into an adult and left his home, promising his mother that he would come to her when needed. Vyasa acquired knowledge from the four Kumaras, Narada, and Lord Brahma. He was also and ardent devotee of Lord Vishnu. Since birth, he already possessed the knowledge of the Vedas, the Dharmashastras, and the Upanishads. Vyasa is believed to have lived on the bank of the Ganga in modern-day Uttarakhand.
In Dwaparayug, all the Vedic knowledge was available in spoken form before Vyasa. Vyasa appears in this yuga for the first time as a compiler of the Mahabharata. Vyasa was also the first to convert all the Vedic knowledge in written form.
Vyasa asks Ganesha to assist him in writing the Mahabharata and other Vedic texts. Lord Ganesha imposes a precondition that he would do so only if Vyasa would narrate the story without a pause. Vyasa set a counter condition that Ganesha should first understand the verses before writing them. Thus, while Lord Ganesha wrote, Vyasa narrated the entire Mahabharata and all the eighteen Puranas and Upanishads.
Puranas say that Vyasa’s twenty-first Guru was sage Vasudev. He studied the Shastras under sages Sanka and Sananda and others. While he wrote Mahabharata, he also arranged the Vedas in right sequence for the benefit of humankind and wrote the Brahma Sutras for the easy understanding of the stuties.
Vyasa's last work was Bhagwata which he undertook at the instigation of Devarishi Narada, who once came to him and advised him to write it, as his goal in life would not be reached without it.
Vyasa's mother, Satyavati, later married the king of Hastinapur Shantanu and had two sons. Both sons died without becoming fathers. Satyavati asked Vyasa to produce children on behalf of her dead sons. Thus, Vyasa fathers princes Dhritarastra and Pandu (By Ambika and Ambalika), the wives of 2 dead kings.
The sequence of events also leads to a third son, Vidura, via the serving maid to the queens. While Vyasa legally does not have any children, another son Shuka born of a celestial Nymph, is considered his spiritual heir. He was the grandfather of both warring parties of the Mahabharata, the Kauravas, and the Pandavas. He was a spiritual guide to young princes.
Maharishi Vyasa's works are as follows:-
Vedas :- 1) Rigveda 2) Yajurveda 3) Samveda 4) Atharveda
Section of Vedas:- 1) Samhita 2) Brahman 3) Upanishads
Vedang ( part of Vedas):- 1) Vyakaran 2) Jyotish 3) Nirkut 4) Shiksha 5) Chhand 6) Kalpa Sutras
Upveda:- Inside all four Vedas, there are 4 Upvedas, 1) Arthveda, 2) Dhanarveda, 3) Gandharvveda, 4) Ayurveda.
Vyasa has also written many Smritis and Darshan Shastras. The Darshan Shastras are as follows:
1) Poorva Mimansa 2) Nyay 3) Vaisheshik 4) Sankhya 5) Yog 6) Uttar Mimansa (Brahma Sutra).
His works of History include Ramayana and Mahabharata.
All Hindu deity's stories consider Vyasa as a Chiranjivi, one who is still living and roaming throughout the world for the well-being of his devotees. It is said that he appears to the faithful and that Jagadguru Shankaracharya had his Darshan in the house of Sage Mandan Misra. He seems to have appeared to many others as well.