There are many light novels where the MC has a girlfriend. One such example could be 'The Magic Academy Chronicles' where the MC's girlfriend plays a significant role in his adventures.
You might want to check out 'The Celestial Bond'. In this light novel, the MC has a girlfriend and their relationship faces various challenges and obstacles, adding depth to the plot.
One such light novel could be 'The Legacy of Eternity' where the MC has kids and their journey plays a significant part in the story.
The main themes likely include young love and the challenges that come with it. The characters in the 'girlfriend girlfriend light novel' are probably navigating their first experiences of deep affection for others. There could also be a theme of self - discovery as they figure out what they really want in a relationship.
There's 'The Protected Hero' where the main character has a sister who is an expert bodyguard, always watching over him. The story has lots of action and adventure.
Well, 'Mystic Shadows' could be a possibility. Here, the MC's half sister is known for her crazy antics and behavior that often throws the story into chaos.
One possibility could be 'Store World of the Hero'. Here, the main character has an internal store that grants him special powers and opportunities throughout the narrative.
The reincarnated main character goes through all sorts of wild and unexpected adventures. From facing powerful enemies to discovering hidden treasures and uncovering ancient secrets.
I'm not entirely sure who the main characters are without having read it in detail. But usually in such light novels, there would be a male protagonist who is at the center of the love triangle or relationship drama.
There are quite a few light novels with such a setup. One could be 'The Mystic Chronicles' where the MC has a sister servant who plays a crucial role in his adventures.
The fact that she is a villain but also a girlfriend means that she has a duality. She is not just a one - dimensional bad guy. She has feelings for the protagonist, and this complex mix of emotions, along with her villainous actions, makes her a really unique character. There's always the question of whether she can change or if the protagonist can fully accept her as she is, which adds so much intrigue to her character.
Often, the MC starts with unique skills or abilities that give them a huge advantage. Maybe they have super strength, magic, or some rare talent.