You might come across fanfic that explores Don's backstory, revealing hidden aspects of his character. Or, there could be alternate universe tales where Don has different powers or a completely different life.
Well, one idea could be a fanfic that explores the backstories of the main characters in Don Regular Show and how it shaped their present. Another could be a crossover fanfic where they interact with characters from another popular show.
I'm not sure specifically as there could be many novels named something related to 'eileen'. It could be about a character named Eileen's adventures, her relationships, or her personal growth story.
Eileen Chang's novel, Love in a Fallen City, was a famous romance novel about the love story between a businesswoman and her boyfriend in the southern Chinese city of Shanghai at the end of the Qing Dynasty. The novel takes the emotional entanglement between the two characters as the main line, and through describing the changes in their fates, it shows the various difficulties of society and the complexity of human nature at that time. The plot of the novel was full of ups and downs, and the writing style was beautiful. It was regarded as a classic in the history of modern Chinese literature.