The People of the Night govern the balance of the night and dreams.
The People of the Night as a whole seemingly consist of Faun, Eel (Phospho) and Nightlings like Mune.
Unlike their counterpart, the People of the Day, the People of the Night are silent, reserved, and have a high regard for what is sacred to them, as shown when Mune interrupted the coronation of Leeyon as the new Guardian of the Moon or when he accidentally destroyed the Nightly Woods.
The People of the Night were said to be the second because the Guardian of the Moon came after the Sun. These silent people awaken the Night and aid the Guardian.