So a bit of information about his fox character:

-The character is literally him turned into a fox.

-Why is he a fox? Because he loves foxes.

-Why is he on fire? Ibby also likes the element fire. 

-Firefox? lolyes, he uses FF, and adores vulpix/ninetail, which adds onto him being a fiery fox! :’D

-Fire comes out at will. When enraged, he’s engulfed with flames.