She was plump and motherly with graying hair. She was 5'8 tall.
She was Aes Sedai for nearly 200 years. She was born in 716 NE.
She was the Mistress of Novices under Noane Masadim and under Tamra Ospenya. She was very good at finding out what novices didn't want her to know, but nonetheless, she was kind and comforting to all novices, and generally warm and easygoing. Most initiates could not figure her out--she could soothe very well, but would go easy on an initiate for one offense only to be a harsh disciplinarian for another, lesser infraction. Still, she was very good to talk to and most initiates went to her on their own more often than for punishment.
After Tamra's death and the rise of Sierin Vayu as Amyrlin, Merean was replaced as Mistress of Novices. She became one of the Black Ajah's searchers for the Dragon Reborn, after they found out that he had been born. Her search eventually led her to Kandor, where she crossed paths with Lan Mandragoran and Moiraine. She tried to kill them, and did kill Diryk, prince of Kandor, Brys, the consort and Swordbearer of Queen Ethenielle Cosaru Noramaga of Kandor, and Iselle Arrel, the daughter of Edeyn Arrel, Lan's carneira. When Merean grew overconfident and turned away, Moiraine managed to kill her with a knife in the back after a severe duel with the One Power. To keep the Black Ajah hidden Moiraine burnt Merean's body.
She bonded a Warder more than ten years after becoming Aes Sedai, and after he died never bonded another. People whispered that she was in love with him. The truth is, he was a Darkfriend; she did not want to deal with a non-Darkfriend Warder, and never found another she thought suitable. She also never felt the need for a Warder as she was not bound by the Three Oaths.
Her name is somewhat of a riddle. Her first name is mirrored in the first Queen of Shienar, Merean Tihomar, but her English-inspired name suggests an Andoran origin. The mystery remains unanswered to this day.