Mushoku Tensei - Jobless Oblige (Novel)

Synopsis

Zieghardt Saladin Greyrat. He is unemployed. From an early age, he wanted only to be an Ally-of-Justice. For that sake, he learned the way of the sword and became strong. However, when he left his hometown, he got a taste of reality and abandoned his dream. He spent his days lethargically wasting away until the day he met this one boy. This is the tale of how the unemployed boy found his way to becoming an Ally-of-Justice [Original Web Novel](http://ncode.syosetu.com/n9038dg/)

Synopsis & details from MangaUpdates