Well, there could be several ways. It could be that they are part of the same community or group. Or perhaps there's a mystery or adventure that forces them to interact and thus, Ruri gets to know Senku. Maybe it's all part of a complex web of relationships that unfolds as the manga progresses.
Well, 'senku x tsukasa fanfic' like 'The Path of Understanding' is really good. It starts with their initial clashes and then gradually develops into a story of mutual respect. 'Shared Visions' is also great as it imagines a scenario where they both have to combine their skills for a common goal. And 'Hidden Depths' reveals the more complex aspects of their relationship through various events in the story.
One great 'senku x gen fanfic' could be 'The Adventure Beyond Stones'. It takes their unique relationship and puts them in a new, exciting situation where they have to work together to overcome a strange new threat in their primitive world. It's full of action and the banter between them is really well - written.
First, study the characters of Senku and Tsukasa. Know their personalities, goals, and what makes them tick. Then, come up with an interesting plot. It could be something like them going on a quest together or facing a new threat. Also, focus on their relationship dynamic, whether it's a friendship, rivalry, or something in between.
First, study their characters well. Know Senku's love for science and his logical thinking, and Gen's skills in psychology and his shrewdness. Then, come up with an interesting plot. Maybe something like they get stuck in a new, uncharted part of the stone world. Start writing, don't worry too much about grammar at first, just let the ideas flow.
One possible moral could be about the importance of kindness. If the kid in the story shows kindness to the lion kid, it might teach that being good to others, regardless of their appearance or power, can lead to positive outcomes.
I'm not sure of the specific full story without more context. It could be a case of a bully targeting a vulnerable blind child, which is extremely cruel. There might be underlying reasons like the first kid having some behavioural problems or being influenced by a bad environment.