One common theme could be power and its consequences. Since Percy is an elder god, he has a great deal of power, and the fanfiction might explore how he uses or misuses it.
I'm not sure specifically which 'Percy is one of the elder goda fanfiction' works are good. You could try searching on fanfiction platforms like Archive of Our Own. They usually have a wide range of works and user reviews to help you find interesting ones.
Yes, some Indian literature may contain stories with elements of human relationships that could be considered in the realm of sexual themes, but they are often presented within the context of cultural, moral, and social values. For example, in some ancient Indian epics, there are descriptions of relationships between characters that might have sexual undertones. However, these are not simply 'sex stories' in a vulgar sense but are part of a larger narrative about love, marriage, and society.
Indian literature is renowned for its depth and cultural significance. It is centered around themes such as caste, religion, and social norms. Tales are more about the human experience in relation to these aspects rather than sexual stories. There may be some modern works that explore relationships in a more liberal way, but they are not the norm and not really about 'hot sex stories' as you put it.
In modern Indian literature as well, authors may write about the emotional and physical aspects of a couple's relationship. However, it is not in a vulgar or pornographic way. It is more about exploring the human nature of love, attraction, and the bond between two individuals, often within the framework of Indian society and its values.
In terms of character development, Indian tribal novels have set new standards. The complex and multi - faceted characters in these novels, with their deep connection to their tribal roots, have influenced how other writers create characters. The tribal characters' relationship with nature, family, and community has provided a new model for exploring human relationships in literature. This has led to a more nuanced and holistic portrayal of human nature in modern Indian literature.
Indian literature is rich and diverse, but focusing on'sex stories' in a general sense might not be the most appropriate way to approach it. However, there are works that touch on relationships and human nature in an intimate way. For example, some of the ancient Sanskrit literature might have allusions to love and relationships which could be interpreted in different ways, but it's not about explicit'sex stories' as such.
Rather than seeking such inappropriate content, one can explore the great epics like the Ramayana and the Mahabharata which teach us about virtues, relationships, and the way of life in Indian culture. These are far more valuable and edifying than any improper or vulgar tales.