I'm going to have to say Imp Midna because we see her develop more, and she's always riding Link in wolf form, so she's much more into the whole adventure.
It's not like she became a whole new person, she's still her self, just in her correct form.
Rank the expansion/DLC characters/weapons from best to worst
HextupleyooDOT Isn't 50 characters a little overkill for a title?
Description: Apr 6, 3, Santa Destroy. I really liked her imp form.