Hacking Ghost: Karada ni shika Kachi no Nai Gakuen

In an era where one in every twenty people has awoken to a "special ability," Hiroto Takigami is a weak ability user who can only communicate with spirits. However, for some reason, his stepsister Rei, the most powerful ability user, harbors deep hatred toward him. The moment he graduates from an ability training institution and gains full control over his power, Rei will kill him. He only has one year left to live. That's when a spirit appears before a despairing Hiroto and reveals an unexpected secret about his ability... An unprecedented supernatural "body takeover" battle begins!

(Source: Kodansha, translated)