There could be a misanthrope as a main character. A person who hates humanity in general, which is quite the opposite of loving others. This character would likely be cynical and avoid any form of positive human connection.
Maybe a jaded ex - lover. Someone who has been through a bad break - up and has now become bitter and represents the opposite of love in their actions and attitude towards their former partner.
A cold - hearted businessperson could also be a main character. They might be solely focused on profit and success, seeing relationships as mere transactions and having no room for love or compassion in their lives, which is the opposite of what love represents in terms of selfless giving and connection.
They could be two young students who fall in love at school. They share the same interests in academics and extracurricular activities, but then face challenges when their families plan to move to different cities.
I don't know since I haven't read the book. Maybe it has a protagonist who is a young person dealing with difficult circumstances.
A knight and a princess from two feuding kingdoms. The knight is sent to fight against the princess's kingdom, but they fall in love. Their love is against the will of both kingdoms, and the battles between the two sides result in a lot of bloodshed, making their love story blood - stained.
It might be a story about two chefs. One works in a high - end restaurant and the other in a small family - owned diner. They meet in a cooking competition and start to fall in love while competing and also learning from each other's cooking styles.
A librarian and a student could be the main characters. The librarian has access to the secret files and notices the student's interest in a particular topic. As they start to explore the files together, love blossoms. The librarian can provide a lot of background knowledge about the university's history and the secrets within the files.
Obviously, the entomologist would be one of the main characters. And probably their love interest, who could be another scientist, or perhaps someone from a completely different field.
Maybe the main characters are the industries that produce plastic and the environment. The industries love to produce plastic for profit, but the environment suffers from the toxicity of plastic, creating a 'toxic love story' between the two.
Another possibility is that Hinata could be the main love interest. Naruto and Hinata had a relationship that developed over time in the original Naruto story. In this fanfiction, their love could be filled with more crazy and troublesome situations, like family objections or some new enemy targeting their relationship.
Sakura would be the central character. In addition, there could be a young and brave local in the opposite world who becomes Sakura's guide. There might also be some shadowy figures that are controlling the chaos in the opposite world and Sakura has to face them to set things right. These characters would all interact with Sakura and shape the story as she tries to navigate this new and unfamiliar place.
There is no way to know for sure without reading the 'love is love novel'. But in many novels with this theme, the main characters could include those who are trying to redefine love for themselves. Maybe there are characters who have been hurt in the past and are now finding a new kind of love that they never thought possible. They could be the ones who drive the story forward by their journey in understanding and experiencing 'love is love'.