[3][4] Princess Allura is ruler of Planet Altea and last surviving member of royal family after the death of her father King Alfor.
In Voltron: Legendary Defender, Allura is the teenage princess of Altea, the daughter of King Alfor and last surviving female member of the Altean race.
In Legendary Defender, she was depicted as Altean, and was re-imagined as being dark skinned with white hair (likely so she was distinguishable from her human allies) and, unlike the rest of the main cast, spoke with a British accent.
Visions while she slept showed the spirit of her father King Alfor promising that five young men would come to Arus in search of the legendary robot Voltron.
When Keith, Lance, Hunk, Pidge, and Sven arrive on Arus and speak of the mighty robot, Allura instantly knows that they are the ones spoken of in her visions, and helps them to find the five hidden lions that will unite to form Voltron.