One idea could be a rengoku fanfic where he trains a new group of young slayers. It could focus on his unique teaching methods and how he instills his values in them.
Tanjiro would be a great character to pair with rengoku. Their different personalities could create an interesting interaction. Tanjiro's kind - hearted nature and rengoku's fiery determination could lead to some great storylines.
Here are some recommendations for novels about how good an older brother is to his younger brother:
1. " My brothers have been reborn."
2. Sister Has Superpowers
3. "Hi, Steamed Bun's Dad"
4. "Reborn 80 Honey Wife"
5. Koi Fish
Please note that the novels recommended above are based on the search results provided and may not be comprehensive or accurate. It is recommended that you check the book's details and reviews before reading to ensure that it meets your preferences and expectations.
One of the main themes is adventure. Since rengoku is often involved in battles and dangerous situations, the fanfics may take the reader along on these adventures. They might face demons together and their relationship develops through these shared experiences. Also, loyalty is a big theme. Rengoku is a very loyal character, and this loyalty extends to his relationship with the reader in the fanfics.
The following were some recommended novels about older brothers taking care of younger brothers: " Older Brothers Reborn "," Sister Has Superpowers "," Hi Bun's Dad "," Reborn Babie's Wife "," Koi Milk Bun Three and a Half Years Old, Six Older Brothers Fighting for Spoiling ", etc. These novels covered different plots such as the older brother bringing the younger brothers up, revenge, and entering an orphanage. I hope these recommendations can satisfy your need for a novel about an invincible older brother bringing his younger brother along.