Well, if by 'best' we mean well - written and engaging, 'Re:Zero − Starting Life in Another World' is a great example. It has a very interesting plot that keeps you on the edge of your seat with its time - loop concept. Regarding 'mature', it does deal with some darker themes and complex emotions. But again, the 'Harme' is a bit of a mystery here. Maybe it was supposed to be 'harmony'? In that case, light novels that have a good harmony of different elements like 'No Game No Life' which combines strategy, comedy, and a unique world - building are great.
I'm not familiar with 'Harme' in this context. However, if we talk about mature light novels in general, 'Kumo desu ga, Nani ka?' (So I'm a Spider, So What?) can be considered. It has a unique perspective as the protagonist is reincarnated as a spider and has to survive in a harsh world. It deals with themes like survival and evolution which can be seen as more'mature' topics. It also has an interesting power - up system.
One popular one could be 'The World of Otome Games is Tough for Mobs'. It has an interesting harem setup with a unique plot. The characters are well - developed, and the story combines elements of a harem with a game - like world, which makes it engaging.
One characteristic is complex themes. Mature light novels often deal with more profound ideas like moral dilemmas, complex relationships, and the darker aspects of society. For example, they might explore how a character copes with the loss of a loved one in a very in - depth way, rather than just a surface - level treatment. Another aspect is the depth of character development. The characters in mature light novels are usually multi - faceted. They have their own beliefs, desires, and flaws that are gradually revealed as the story progresses. Also, the writing style may be more sophisticated, with more detailed descriptions of emotions, settings, and events to create a more immersive reading experience.
Some great mature light novels include 'Spice and Wolf'. It combines elements of economics and a budding relationship between the main characters in a very interesting way. 'The Melancholy of Haruhi Suzumiya' can also be considered in this category as it has a rather complex narrative structure and explores various aspects of the characters' personalities. 'Fullmetal Alchemist' is another example. It tackles heavy themes like morality, sacrifice, and the cost of power.
Dark and mature light novels often deal with complex themes such as human nature's dark side. They may explore topics like death, moral ambiguity, and the consequences of power. For example, in some, characters face difficult moral choices that have no easy answers.
The themes in mature yuri light novels can be quite profound. Such as the exploration of identity in a relationship. The characters might be struggling with their sexual orientation and how it fits into their lives and the society around them. Moreover, the storylines are usually more intricate, with more twists and turns that keep the readers engaged.
One popular mature yuri light novel is 'Citrus'. It delves into the complex relationship between two girls, Yuzu and Mei. Their relationship starts off rocky but gradually develops into something deeper and more meaningful. The story explores themes of love, self - discovery, and family in the context of a yuri relationship.
The 'No Game No Life' light novel has some NSFW undertones. It's set in a world where everything is decided by games, and the relationship between the two main characters has some flirty and suggestive moments. It's a great read for those who like strategic thinking in the plot along with some adult - like interactions.
I also recommend 'Altered Carbon' by Richard K. Morgan. Set in a future where consciousness can be digitized and transferred between bodies, it explores themes of identity, immortality, and the divide between the rich and the poor. The world - building is top - notch, with a dark and seedy underbelly to the high - tech society.