The Sky Evolution Stone's purpose is to control a person's destiny, making it all seem reasonable while producing challenges that those undergoing trials can accept, aiding in their strength growth.
Some can accept the setting of a ring's old grandfather, then the Sky Evolution Stone manipulates fate to cause the fall of a powerful being, and lets this powerful being guide those under trial to become stronger.
Others can accept the setting of reincarnation and rebirth; thus, the Sky Evolution Stone forges memories, making them believe they're reincarnated, and uses these false memories to guide them in becoming stronger.
Since he has regained the memories from his time on Earth, he can naturally accept the way of guidance from a system to grow stronger, which means the Sky Evolution Stone is very likely to have forged a system to help him become powerful.
