In my book series, I have a character that's been there since book one, with a ridiculous nickname that he's always hated. In book 5, he hints that he would like to change his name, and now I'm 1/4 into the manuscript for book 6. My plan was to change his name in the time-gap between five and six, but now that I'm writing about him with the new name, I feel like something's off, like something that made him him is gone. Still he has a very weak personality, that's sort of part of the plot, and changing it would never bother him in any way. My test readers have liked it so far... what do you guys think?