In the days that followed, Yanbai would wait for Madara Uchiha to bring back good news from another virtual world, while soothing Black Zetsu whenever he appeared.
Kaguya was the incarnation of Yanbai's "Old Grandmother" in the Shinobi World.
"Old Grandmother" was the creator of all the virtual worlds. Of course, the Shinobi World was not the only virtual world she had created; she had made many others.
In reality, "Old Grandmother" had abandoned her physical body so that her consciousness could travel throughout the network of virtual worlds. She had transformed herself from a flesh-and-blood human into an artificial intelligence, living forever within those online worlds.
Immortality was terribly boring. "Old Grandmother" had created many different virtual worlds, which meant she had a great many worlds to manage.
In every virtual world, "Old Grandmother's" incarnation was its strongest being. Ordinarily, however, that incarnation remained sealed, because her consciousness would not linger long in a world she disliked.
The "Virtual Hokage Shinobi World" had been created to meet player demand. To "Old Grandmother," it was hardly a suitable world for sightseeing or entertainment, and she did not like staying in the Shinobi World.
That was also why Old Grandmother had told Madara Uchiha back then, "If we are to meet again, you must activate Infinite Tsukuyomi."
After reaching an agreement with Yanbai, Old Grandmother had sealed her incarnation, Kaguya, again and sent her consciousness to other worlds.
Activating Infinite Tsukuyomi was equivalent to triggering a summoning mechanism. Whatever Old Grandmother was doing, she would have to return to the Shinobi World and play Kaguya again. Then she would go absurdly easy on those who had broken the seal, allowing herself to be sealed once more.
Yanbai's situation was the same as his "Old Grandmother's."
Yanbai had his own incarnations in