It could also be due to a personal revelation. Suppose he discovers something about his past, like a hidden family secret or that he was unknowingly involved in something bad. This new knowledge could be so overwhelming that it brings him to tears. For instance, finding out that his family was involved in a dark plot against the village many years ago and he now has to deal with the consequences of that revelation.
One reason could be the loss of a fellow shinobi. In the Naruto universe, comradeship is highly valued, and if Kotetsu were to lose someone close to him in battle or otherwise, it would be a very emotional moment that could lead to crying.
Maybe he fails in an important mission. Kotetsu is a shinobi, and his job is to complete missions successfully. If he fails, especially if it has significant consequences for the village or his friends, he might feel a great sense of guilt and disappointment, which could cause him to cry. For example, if his failure leads to the capture of an important ally by the enemy.
Finding a specific 'Naruto' fanfiction with Kotetsu crying can be a bit of a challenge. First, you need to consider the different aspects of the story that could lead to such a situation. Maybe it's during a battle where he loses a comrade, or perhaps a personal struggle within the Hidden Leaf Village. Then, use these ideas as keywords when searching on fanfiction platforms. Additionally, joining Naruto fanfiction communities and asking for recommendations could also be a great way to discover such a story.
One possible reason could be that Naruto is feeling lonely. Despite having friends, he still has moments when the weight of his past, like being an orphan and ostracized in the village as a child, hits him hard. Jiraiya might see Naruto crying because of these memories resurfacing.
One possible reason could be the loss of a dear friend. Naruto forms deep bonds with his comrades, and if something were to happen to them, like Sasuke leaving again, it would break his heart and make him cry.
One possible plot could be that while they are sick, their comrades in Konoha come together to take care of them. Maybe Naruto brings them some of his favorite ramen, thinking it might cheer them up and help them get better.
Maybe Wendy is crying because her favorite Pokemon got hurt in the fanfiction. It's really sad when a beloved Pokemon is in pain.
One possible reason could be Loki's sense of isolation. In many Avengers fanfictions, Loki is often portrayed as an outsider. He may cry out of loneliness, feeling that he doesn't truly belong anywhere, not even among his own kind. Another reason might be regret. Loki has done a lot of wrongdoings in the stories, and he could be crying over the consequences of his actions, like the harm he has caused to Thor or the people of Asgard.
Maybe he's missing his family. He's been away from them for a long time on the Argo 2, and homesickness could hit hard and make him cry.
One possible reason could be the loss of his friends. Naruto values his friends deeply, and if he were to lose someone like Sasuke again, it would be devastating. Another reason might be the pressure of being the Hokage. The responsibilities are huge, and he might feel like he's not living up to the expectations of the village. Also, memories of his lonely childhood could resurface, making him feel sad and alone, leading to him crying himself to sleep.
One possible reason could be that he is lonely. In many fanfictions, Naruto is often ostracized as a baby due to the Nine - Tails inside him. He might be crying because he feels the lack of a warm, loving presence around him.
One common theme is loyalty. Kotetsu is often depicted as being extremely loyal to the Hidden Leaf Village, and fanfictions explore this loyalty further, like in situations where he has to choose between the village and his personal beliefs.