I love nicknames for characters and 'fancy boy' seem to match Dubois really well!
For mine, I'm not sure if they count as nicknames if they were used only once to describe a character, but I'll include them anyway because I like them
Most of the time my characters are called 'poor baby' or 'my baby'
Blanka / Kestrel : just yesterday was called 'ptaszyca' - which is hard to translate as it is not a properly used word but in this context it would mean a giant female bird;
Jerzy :
- Jerzey / Jersey - this one was used a lot, to this day I don't know if it's a nickname or just attempts at pronunciation;
- 'the boy can repair himself' has to be by far my favourite;
Maya: my sister calls her 'krasnal' - which means a dwarf or a gnome; also 'Maya in the Garden' because there is (was?) a polish tv program with this name about gardening
Max: 'freckle boy'; fun fact, my scanner loves to remove his freckles and I have to draw them digitaly most of the time;
Mërgim / Dreams King (he was not named in the series) : I'll go with an exact quote, 'the boy in the book'. Fun fact, he is not in the book
OKAY THIS ONE DOESN'T HAVE A NAME YET : soul snatcher; the Winged Guy in Black; 'diobeł' (the last one means a devil in a subdialect)