[Masanori Ota]

Originally Posted by xris

This is inaccurate. She has the appearance of a 15 year old girl but her actual age? Perhaps a manga reader can tell us if this has been stated or implied.

Spoiler for Horo's age as stated in the novel:

Around 600 years old is Horo's actual age, if not more. Horo herself said she had lived as many years as she had hairs on her tail, but that was probably hyperbole.