I'm a fan of online literature. I don't have any knowledge of NTR because it's usually used as a negative term and is not suitable for novels. In novels, milder and more appropriate words are often used to express similar meanings such as betrayal, deception, murder, etc. If you have any other questions, I will try my best to answer them.
Well, 'ntr fiction' typically refers to stories that revolve around the concept of 'netorare' in Japanese. It can involve love triangles or situations where one character's relationship with another is interfered with in unexpected and often emotionally charged ways. It might show how characters deal with jealousy, betrayal, or unexpected changes in their romantic relationships. It's a rather niche genre in the world of fiction.
NTR manga typically involves a situation where a character's romantic partner is stolen or has an affair with someone else. It's a genre that can be quite controversial.
There is also 'The NTR World'. This novel stands out as it not only shows the ntr relationships but also delves deep into the psychological aspects of the characters. It makes the readers think about loyalty, love, and betrayal in different ways.
The 'lemon' aspect might be a bit hard to come by in a clean way as it often involves inappropriate content. But for normal Korra and Mako fanfictions, you could also try FanFiction.net. Some stories there might show their relationship developing, their adventures together, and how they support each other, which can be really interesting to read.
The 'Haruhi Suzumiya' series also has some elements that might be related to relationship exploration. The story is centered around Haruhi and her friends, and there are various interactions and relationship developments among the characters that could be considered in the context of complex relationship V novels.
Korra could meet the founders of the different bending disciplines. She could meet the first water benders and learn about the purest form of water bending. This would not only enhance her own skills but also give her a deeper connection to her water - bending heritage.