Mythical (6)
'mythical' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for legendary that I've seen before include "Relating to old or mythological tales" , "notorious" , "Mythical - very famous" , "Well-known" , "Based on myth or famous for achievements (9)" .)
(Other definitions for storybook that I've seen before include "Child's reader; perfect" , "Ideal" , "Collection of children's tales" , "Fabulous" .)
'mythical' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fabled that I've seen before include "noted" , "Told of in legends or myths" , "Enshrined in ancient stories or legends" , "Well-known" , "Legendary, mythical" .)