Which king broke up the kushan empire lands?

The Kushan Empire began to decline under King Kanishka, who ruled in the 2nd century CE. However, it was during the reign of subsequent rulers, particularly in the 3rd century, that the empire fragmented due to internal strife and external pressures. The empire ultimately fell apart as various regional powers, including the Sassanids and emerging Indian states, took control of different territories that were once part of the Kushan Empire.