Immortal With A System?

Akemi was the most powerful immortal of another world. Why did I say "was"? Oh because he's been reincarnated into the body of a powerless 15 year old high school boy named Lian Xu, after being betrayed by his best friend Toru. Upon waking up into his new body Akemi saw a strange window that called him a "player" that only he can see. Follow Akemi as he is reborn into a new world where Lian Xu has been abandoned, used and mistreated by everyone, a world where the strong are respected and the weak are thrown away, What will Akemi the former immortal do?