The Aes Sedai are separated into three groups: the Red Ajah, the Blue Ajah, and the Yellow Ajah. Moiraine and Maigan are both Aes Sedai of the Blue Ajah, the group known for its strong sense of justice and dedication to fighting for what is right. Maigan is introduced in Season 1, Episode 6. She is not afraid to criticize Siuan (Sophie Okonedo), the leader of the Aes Sedai.

Source: https://www.distractify.com/p/maigan-wheel-of-time