He need to find another class in the swordsman tree to learn new moves.
If Sword God is the highest level in the tree, the backstory of that person is sad
Some WN, and many LN and manga have variations of the concept of "social mercy". Rather than ruthlessly finish the bad people off while gloating, you try to reform them even though their past is full of recidivism. Since I see the original story in some author's posted WN be much harsher than the printed LN or manga, I assume it is the story editor assigned by the media publishing company that softens the story in order to avoid criticism from those who defend criminals and are always highly vocal about it. In the early days of anime, this was also a criticism point when the Japanese production company admitted a USA partner (e.g. Universal) to help defray the production costs or to have simultaneous release in worldwide markets at the cost of self-censorship or elimination of certain non-progressive situations.