I'm not sure which Levi you specifically mean here. There are many characters named Levi in different stories. If you're referring to Levi Ackerman from 'Attack on Titan', his friends in the Survey Corps faced numerous deadly encounters with Titans. Many died during expeditions outside the walls, being devoured or injured fatally by Titans while trying to protect humanity and gain knowledge about the outside world.
Levi x His Mother fanfiction could potentially show a deep emotional bond between them. It might be used to fill in gaps in the original story about Levi's past. For example, it could depict his mother teaching him important values or skills. But some might find this concept a bit odd as it blurs the normal boundaries of family relationships in fiction.
One of Primo Levi's friends might have had a story of finding hidden food sources in the concentration camp to survive. Maybe they had to outwit the guards to get an extra ration of bread.
It would likely make him more mature. Knowing about his parents would give him a different perspective on life. He might be less reckless in battles as he now has a family connection to think about.
One great fanfiction with this theme could be on Archive of Our Own. There are many talented writers who explore Link's past life in unique ways. Some might show him remembering his past life as a heroic knight in a long - lost era, with vivid descriptions of battles and his comrades from that time.
The emotional impact could be huge. Goku has mostly been without his parents in the main story. Remembering them in a fanfiction could bring out a sense of longing and sadness. He might feel a deep connection to his Saiyan heritage that he was previously unaware of. This could also lead to a newfound motivation in his battles, as he now has a connection to his roots.
I recommend "The Legend of Online Games". This novel is a gaming-game-otherworld-type novel. The protagonist comes to a mysterious challenge space. It's actually a world that looks like an online game. There are endless missions waiting for the protagonist to complete. And the benefit he received was to rule the entire world! The plot of this novel is very similar. Perhaps it's what you're looking for. I hope you like this fairy's recommendation. Muah ~😗
If we are talking about Levi Ackerman again. His comrades in the Survey Corps were constantly at risk. Petra, Auruo, Erd, and Gunter were part of Levi's special squad. During an expedition, they were faced with the Female Titan. Their deaths were tragic. They fought bravely but were ultimately outmatched. The Female Titan was able to use her intelligence and strength to defeat them one by one. This was a huge blow to Levi as they were not only his friends but also some of his most reliable subordinates in the fight against Titans.
One aspect that could make it interesting is the exploration of Levi's origin. Since his mother is a part of his past, fanfiction can provide insights into how she might have shaped the person he is. For instance, if she was a strong - willed person, it could explain Levi's own determination.