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.
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.
Generally speaking, the parting words of a novel were usually to describe the deep feelings and reluctance of the parting, to express the nostalgia for the protagonist, and at the same time, to let the reader feel the sadness and helplessness of parting.
There were many forms of parting words commonly used in novels, such as:
1. Leave contact information: Before leaving, the protagonist will usually leave his contact information for future contact. This method was often used to describe the protagonist's deep feelings and reluctance.
Blessing the other party: Before parting, the protagonist will usually wish the other party a happy life. This way, it could express the protagonist's blessings and concern, making the readers feel warmth and care.
3. Missing: Before parting, the protagonist would usually write down some words of longing to express his longing and reluctance. This way, the readers could feel the protagonist's inner feelings and the pain and helplessness of parting.
4. Farewell to the good times: Before parting, the protagonist will usually recall some good times to express his nostalgia for the past. This way, the readers could feel the protagonist's deep affection and reluctance, and at the same time, it could also make the readers feel the passage of time and the short life.
The parting words of the novel was a very imaginative and emotional way of expression. It could let the readers feel the inner feelings of the protagonist, the pain and helplessness of parting, and at the same time, it could let the readers feel warmth and love.
Well, some popular rengoku x reader fanfics can be found on Wattpad as well. Look for ones with high ratings and good reviews. They usually offer different storylines, from adventure - filled ones where rengoku and the reader go on quests together, to more romantic and heart - warming stories about their relationship.