Caste system was not started by a particular person.
It was just a way to discriminate between people and society depending upon the work or profession they do. During the Rig Vedic Period (BC 1500–1000) the caste system was open and it was flexible. This model was based on occupation and was called the Varna System. Depending upon this model there were 4 castes
1. Priest or Scholars (Brahman)
2. Kshata (Ruling Class Kshtriya)
3. Vaishyas (Service Class)
4. Shudras (Inhabitants of the territory acquired by the ruler)
Since this model was flexible and interchange of Varna was possible.
Anyone from Shudra varna could acquire knowledge and change his varna to Priest or Kshata or Vaishyas. It was up to his will to choose the occupation and change his varna.
But in the Later Vedic Period (BC 1000–500) this system was changed to Rigid. So, interchange of varna was not possible and it was strictly to be adhered.
It would have been the Priest Class which must have made this system rigid so that they can maintain there supremacy over the other citizens for eternity.
Now, B.R Ambedkar, who wrote Indian constitution, and created a reserved quota for a particular caste, made it even worse.
In vedic period it was occupation based, but later on it became hereditary.
The caste system was 'a division of society to preserve society' similar to the society in ancient Egyptian times. Each group had rules of conduct to be obeyed.
The caste system divided people by occupation i.e. teachers and philosophers were brahmins; fighters were kshatriya; shopkeepers, moneylenders and tradespeople were vaishya; and servants and cleaners were shudra.
No caste was higher or more important (superior) to another. All were equal and acknowledged as essential to the society.
