What was the essence and purpose of the oprichnina?

The purpose of the introduction of the oprichnina was to strengthen the tsarist power, as opposed to the then existing feudal fragmentation, which led to the concentration of unprecedented power and power in the hands of a large number of princes.
The essence of the oprichnina was the implementation of widespread, total terror, the source of which was the central government, that is, the state. At the same time, a large number of executions were carried out on the basis of absolutely unverified information and cruel reprisals were committed.