Time Travel and Rebirth, Phoenix Nirvana

I'm not a loser! I wonder how I, a top assassin capable of both civil and military skills in modern times, turned into a loser in ancient times. I don't accept my fate! Watch me take revenge one by one on those who regard me as a thorn in their side and a thorn in their flesh! Huh, even in ancient times, I had the courage of a phoenix!