Nova is a fairy at Alfea from Solaria. Her first appearance is in episode 4 of season 3. She is from Solaria, the same realm as Stella. She helps fill in the news for Stella and tells her the latest gossip for Solaria. When the Winx went to Andros to slow Valtor's takeover of the realm Nova helped Stella cover up for them.
Nova also helps Stella and the Winx Club to sneak into King Radius's wedding kwa suggesting they impersonate the flying biker troop.
First appearance: The Mirror of Truth
Age at first appearance: 16
Affiliations: The Winx (friend), Alfea, Solaria
Relationship: Stella(princess and long time friend), unnamed mother
Info from winx club wiki
Nova's magic winx outfit