Reincarnation Paradise [EDITED]

Su Xiao is a cold-blooded teenager who’s seeking vengeance for the death of his family, yet things ended up badly for him. As he was taking his last breaths, he heard a voice calling him from dimensions, it was a strange system reaching him, asking him if he wanted to be saved, to be Reincarnated. He just needed to accept a contract, Su Xiao didn’t have any choice but to do so, but he didn’t know what he signed up for!! Traveling through worlds, doing extremely dangerous missions, collecting special items, leveling up, and even killing Protagonists… But Su Xiao wasn’t any ordinary Contractor, Su Xiao was a Hunter! The MC crosses over to: One Piece, Tokyo Ghoul, Naruto, Fullmetal Alchemist, Attack on Titans, Akame ga Kill, Hunter x Hunter… Note: If there are words or sentences that you don't understand, you can tell me in the comments.. Thanks :) My Target of this Novel is up to 3000+ chapters or until the last chapter of Raw Novel release!! [1 up to 3 Volumes Novel per Week]