A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Kyria d'Oreyn
Unless stated otherwise, all information herein is taken from The Great Hunt, Chapter 23.
Malena Aylar is the Wisdom of Emond's Field during Nynaeve's testing for the ring, so she is most likely an imaginary character. She is tall and scrawny.
She came from Watch Hill to see Mavra Mallen one day before Mavra had to go back to Deven Ride. Afterwards, she stayed to tend the sick and see to the dying sheep, so the Emond's Fielders elected her as their new Wisdom.
She is a bully and had Cenn Buie elected as Mayor after she poisoned Bran and Master Luhhan, because they did not walk in the Light, or so she claimed.
She once beat up Alsbet Luhhan with a stick, but no one ever does anything against her, because they are afraid of her fierceness. She lets children fall ill to have a reason to stay a while longer.