Elyon
Didn't he have extra millennial beast core? Why did he not use it to level up his own level? So he can use extra stat to endurance? Feels like mc is just making his life harder when there's a shortcut, there's no side effects so why don't he use it? If there's one, then his system is mediocre at best, But the title is Reincarnated with the STRONGEST SYSTEM" so there's should be no disadvantage;