Todays human is scientific where as human of satyuga was only vedic. Actually as the time passed when Brahma ji gave knowledge how to speak lie, the human started stateing the meaning of vedic mantras and first got divided into Deva and Asura. As in vedas it is very well stated that Lord Shiva exists in three states aakar (Sankara) Saakara (Sun) and Nirakar (Shiva).
The devas followed the practices by makeing a change in the vedic system which gave birth to brahmins, chatriyas, vashyas and shudras. The people who did not followed the worship process of shiva lingam were called as Asuras. People who refused to worship the stone as god were called as asuras by the people who started worshiping the shiv lingam. There came many fights between them on religion only which made trilions of people die in different fights (Dev-Asur Yudhs).
The asuras belived in vedas only as shukalyajurveda says there is no visible shape, size ect of lord shiva and shakti. The termology of asuras was logically more reliable on vedas. As Ravana took birth as a Asura and as a deva (Brahmin). Ravana did the first khatna of his lingam on the planet due to which he was called to kailash by shankara for clarification of this act. Ravana told very clearly to lord shiva that, the place of heart is the place of brahma, the place of skull is the place of vishnu and the place of lingam is only shiv stahana. For a loyal (Iman Vala) human it is very necessary to keep this perticular very private place neet and clean as it is only present in male body.
The ladies has the shakti sthana for production. This act of ravana gave birth to one new relegion as plenty of people started following this act for neetness, puriety and cleaness of the body. Ravana was the first Loyal Brahmin on the planet. People of the planet got divided which gave birth to two anti religions.
At present time it is very well seen the human of present time is divided into plenty of Religions and not following the chanting of vedic mantras, for which human is born on this planet. Each human has an oath, but human of present time does not have the knowledge of his oath, where as the Rishis achived the knowledge of their oaths by chanting of mukti mantra. There is no other way on the planet to achive the knowledge of the oath from lord shiva.
After achivement of this knowledge the human should imedeatly start learning the perfect chanting of these important mantras and forget the religion. Human should distroy all religions and should start following the vedas which is only and only sanatana on the planet. The sanatana is a Practise (Pratha) where as religion is a culture (Vayavastha).
How Human got Devided into different types of Religions