Hello,
The story which I have heard on Hinduism and the advent of Buddha is produced below. Even though this do not completely pertain to the question, still I write it is relevant to this very interesting topic.
Hindus celebrate Buddha as the ninth avatāra of Lord Viṣṇu.
Initially, traditional India followed the Vedic division of society known as the varṇa-āśrama dharma. In the varṇa-āśrama dharma, the intelligent class who studied and taught the Vedic sciences are Brahamanas. And, a person was considered to be Brahamana based on merit (actions and qualities), and not on being simply being born into a Brahamana family (caste system).
The Vedas enjoin many sacrifices for serving a higher purpose. For example, there is go-medha sacrifice, where an old cow is sacrificed on an altar and the Brahamanas give the cow a new body by the power of the Vedic mantras. This benefited both the cow and the Brahmanas who would use its milk, butter, urine etc. for religious purposes.
However, with the passage of time the varṇa-āśrama dharma system degraded and was replaced by caste system. Unqualified Brahamanas started performing Vedic sacrifices to satisfy their taste buds and of those who would pay for the performance of such sacrifices.
In the name of the Vedas and Vedic sacrifices, animals were being slaughtered mercilessly. The Hindu civilization lost the aim of the Vedas - which is the realization of the Supreme.
Supreme Lord Śrī Kṛṣṇa declares in the Bhagavad Gītā.
sarvasya cāhaṁ hṛdi sanniviṣṭo
mattaḥ smṛtir jñānam apohanaṁ ca
vedaiś ca sarvair aham eva vedyo
vedānta-kṛd veda-vid eva cāham
[Bhagavad Gītā 15.15]
I am seated in everyone's heart, and from Me come remembrance, knowledge and forgetfulness. By all the Vedas am I to be known; indeed I am the compiler of Vedānta, and I am the knower of the Vedas.
It was then that the Supreme Lord advented as Buddha. He taught ahiṁsā, or non-violence, and that the humans will achieve the highest benefit by helping each other. As the Vedas were in the center of it all, He rejected the Vedas.
Thus, the Supreme Lord appeared as Buddha, according to the time, place and circumstance, to rescue the conditioned souls from the clutches of ignorance (māyā), and show them the path of eternal welfare.