Rajeev Misra is stepping back from his main roles at SoftBank Group Corp., marking the exit of one of the key architects of the Japanese conglomerate’s sometimes chaotic evolution into the world’s largest technology investor.

A key lieutenant of SoftBank’s founder Masayoshi Son, Misra will retain a senior position with the group’s first $100 billion Vision Fund, but relinquish other roles, people familiar with the matter said.

Misra recently held talks with Son in Tokyo, during which he told his boss of his plans to leave to pursue his own venture, according to the people, who asked not to be identified discussing confidential information.