Maenad

Maenads were wild but good nymphs, who followed Bacchus. These pretty, vivacious nymphs were madcap young girls with black hair.

They are physically identical to human girls, and are not proper nymphs, such as Dryads and Naiads.

Aslan
When Aslan returned during the Narnian Revolution just after the Telmarine Conquest of Narnia, the Maenade flowed out of their trees at the sound of his roar. They gathered around Aslan, Lucy, and Susan, bowing, curtsying and waving their beautiful thin arms at them. Lucy saw that the Maenads were carrying grapes on platters around Silenus who was riding a large donkey. Just before the end of the Second Battle of Beruna, Bacchus and the Maenads traveled with Aslan and the Queens of Narnia, leaping, rushing, and doing somersaults along the way. Arriving at the bridge they met the River God, who managed to destroy the bridge in order to stop the Telmarines from retreating from the Old Narnians advances. Two of the Maenads join hands with Gwendolen, who whirled her around in a merry dance.

Adaptations
Since Maenads didn't appear in the 2008 Disney Film, they have only been visually portrayed in the BBC adaption. They are shown as human-like natives who carried spears, swords, and bows and arrows and fought together with the Old Narnians. Maenads were first present at the bonfire where they were dancing around the fire with the talking beasts and the fauns, and some of them played the drums as well. Two of them took Caspian X to join them in dancing around the fire.