@Disguised Person
Spoiler!
I don't remember properly, however, since the ML of the second plane created the third plane by unfair means, the third plane is kind of unstable. And also, the rift where he was lost for 8 years, actually responded to MC. The rift was open but soon closed as MC stepped in. Why? Don't ask me. Time inside of the rift is kind of like a time machine, where you can leap to the future faster. I think ML of the second plane helped him or something because he is stuck inside the rift to stabilize the plane, if he is gone then the plane will start falling out.