What's the name of the series please?

In the series the protagonist starts as being a useless no who helped a wounded master but upon his dead he gave his powers to the star, but having no martial arts training he couldn't control it until he met a master who have a school.
The master was killed by an acquaintance of the star using a very powerful sword, later the star picked his dead master's sword and revive it.
Pls help I've forgotten the name of the series.