I'm creating a story with this title and the setting I'm supposed to have is in ancient China. It would be helpful if you can show me how it is spelled and if the translated version sounds more like an endearment from an older boy to a younger boy. Thank you!
Since your story background is in ancient China, expressions such as 我的小鬼 seems to be inappropriate. If you're considering making the story in Classical Chinese, the following words may be helpful:
- Calling a younger brother: When both are young, the older can call the younger by his nickname/infant name; When grown up, the older should call his younger brother by Zi (a certain nickname used to refer to someone respectfully).
- Offensive expressions used for cursing: 竖子, 小子, etc.
If you still want to use modern Chinese, you can simply use:
弟弟, 老弟, 小屁孩 (contemptuous/joking)
I finished this in a hurry so I didn't have time to provide the words' pronunciations. Type those words in Google Translate and you'll get corresponding Pinyins, mostly accurate.