Zera was a young girl who was the daughter of Jezelf, the Guild Master of Red Lizard.
She died in X679 during Blue Skull's raid on Tenrou Island but was used as Mavis Vermilion's illusionary friend until X686. Mavis has unconsciously made Zera as an illusion, so she has believed that Zera was actually real all this time. Yury Dreyar said to Mavis that nobody can see Zera but her and Zera said to Mavis that she will always be in her heart, before disappearing. Mavis could not make her reappear again, as she was fully conscious that Zera was an illusion.