Back From Black

Zak, the greatest assassin to ever live, gets betrayed and killed, only to wake up two centuries later in a bioengineered body. Having been unable to save his wife and keep his promise to her, Zak uses his new body, and the Nano-technology hidden within, to navigate through a new futuristic age of assassins and seek out the ones responsible for his tragedy. Source: Webtoon Includes 1 epilogue chapter.