Since I'm not familiar with this fanfiction, I can only guess. It could be that the bone welder has some special significance in the Naruto universe in this story. Perhaps the bone welder is an important craftsman who is being targeted by bad guys because they want to disrupt some kind of balance. Naruto, being the hero, steps in to save the bone welder and in the process, might also learn something about the importance of this unique profession.
I'm sorry, I haven't read this specific fanfiction, so I can't summarize it directly. But generally, it might involve Naruto using his skills and abilities to rescue a person who is a bone welder. Maybe Naruto discovers the bone welder in a dangerous situation, like being trapped by enemies or in a natural disaster, and then he uses his ninja techniques such as shadow clones or rasengan to save the day.
Chapter 521, "Stick to One Line of Work", is the clearest early answer because it turns Of's situation into a concrete plot event.
Chapter 367, "Help Me Call the Police", is the clearest early answer because it turns Chixia Village's situation into a concrete plot event.
Chapter 346, "This person doesn't seem to like her very much", is the clearest early answer because it turns Assistant Ge's situation into a concrete plot event. The chapter turns that into something concrete by moving from Yes," Jiang Li said, "I learned that this 'Night Walk' is an...
Chapter 379, "Is This the Way Huaxiu Treats Its Guests?", is the clearest early answer because it turns Madam's situation into a concrete plot event.
Chapter 162, "Jiang - Boyfriend Power Explodes - Li", is the clearest early answer because it turns Boyfriend Power Explodes's situation into a concrete plot event. The chapter turns that into something concrete by moving from He Yun then realized what was happening and subconsciously wanted to...
Chapter 532, "Little Lolita Beats Up Jungle Python?!", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Outside the cave, the four people grasped their weapons tightly and...
Chapter 437, "A Gentleman's Revenge is Not Too Late Even After Ten Years!", is the clearest early answer because it turns Shang Shuyue's situation into a concrete plot event.
Chapter 163, "She Actually Gave President Shang a Zero?!", is the clearest early answer because it turns Su's situation into a concrete plot event. The chapter gives readers a real answer by opening on Su Yinwan entered a small room, guided by a staff member.
Chapter 314, "The teacher will surely cultivate you into a new music star!", is the clearest early answer because it turns Zhou Wenshu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with After chatting with Zhou Wenshu for a bit, Jiang Li called Jiang...
Chapter 548, "A Guy Named Gu Yu", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event. Early on, No, we can't," Su Yinwan blurted out subconsciously.. By the end, I see some protective gear has been updated in the store; we could....