Sa Mihai was the female lead in the Japanese manga Death Note. She was a petite, cute, innocent, optimistic, and cheerful artist. She was a model for a teen magazine and was called Misa by her fans. Mihai Sa received the Death Note from Rem, the God of Death, and became the second Kira. She fell in love with Yagami Moon at first sight. She had a crazy infatuation and love for Ye Shenyue and was willing to give up everything for him. She even exchanged for the Eye of Death twice at the cost of losing half of her remaining lifespan. However, Mihai Sa's actions were often seen as foolish and even brought trouble to Ye Shenyue's plans. In the end, on the second Valentine's Day after Moon's death, she chose to commit suicide. The role of Amisa Mihai played an important role in the Death Note, but her fate was also tragic.
You can try some fanfiction websites like Archive of Our Own (AO3). There are often a lot of fan-created stories about different characters, including ones related to Light and Misa from Death Note. Just use the search function on the site and type in relevant keywords like 'Light Misa lemon' to see if there are any stories that match what you're looking for.
Misa's death in the manga occurs due to a combination of circumstances and the web of the storyline. It's a moment that has significant implications for the overall narrative.