"Hello. My name is Zelen, and that's all you need to know."
Being number eight in line, Zelen is basically the "middle sibling" of the Dragon King's fifteen children, though she generally doesn't use her Princess title unless she's on official business. The offspring of the King and a moon elf, she usually stays in her form as an elf, only taking on dragon form when she absolutely has to.
All dragons are essentially born into the "wrong" species, but Zelen (as a child simply known as "Zel") always felt she was born into the wrong gender as well. Dragons are shapeshifters and with time and practice may learn to take on any gender they want, but most of them identify and are most comfortable as the gender they were born into. The young Zel was an exception, though -- born male but always with this feeling that he was supposed to be female.
As the years passed and Zel reached puberty, he learned to take on dragon form and afterwards worked hard on further developing his shapeshifting abilities, always with the goal of taking on the female form he knew he was supposed to have. Determination paid off, and by the time Zel was old enough to receive his adult name, he had learned to become a she. And so, after a bit of debate, the adult name given to her was the distinctly feminine "Zelen," and she was officially recognized as a woman, and given the title "Princess" instead of "Prince."
Because of all the practice made in her childhood, Zelen is unparallelled among dragons when it comes to shapeshifting; she can take on just about any form and physically mimic almost any person she knows, no matter what gender or species they might be. She is in fact one of very few dragons alive who can shift between forms without having to go in between her dragon form first -- and the only known dragon to be able to drastically alter her dragon form.
This, combined with some very good acting skills, makes her the ideal spy -- even if all dragons will instantly recognize her as a dragon no matter what shape she wears, it's near-impossible to identify her as "Princess Zelen." Hence, she is often the one sent out to gather intelligence. That said, she still feels most comfortable in her form as a female moon elf -- the form she first took when becoming female for the first time.
A calm, solemn and serious woman, Zelen is known as one of the most fair-minded and reasonable of the dragon royals; in her role as Dragon Law Enforcer she is always willing to hear other dragons out and is mostly inclined to be merciful, focusing more on protecting the innocent than protecting the guilty. Don't mistake her for being soft, though -- once she has passed judgement it's always final, and justice is carried out swiftly and efficiently.