Introduction
Manthara is the maid of Queen Kaikeyi, described in the Ramayana as hunchbacked (kubja). She is the person whose advice persuaded Kaikeyi to ask for Rama's exile.
This article primarily follows the Valmiki Ramayana. Where a well-known detail comes from a later retelling or tradition, the article identifies it.
The turning point
Manthara came to Kaikeyi on the night before the coronation and told her that Rama's rise would ruin her and her son. At first Kaikeyi was delighted at the news. Manthara continued until Kaikeyi's feelings turned, and she reminded the queen of the two boons owed by Dasharatha.
After the exile
When Bharata returned and saw Manthara, he wanted to punish her, but he did not act, because Rama would not have approved. Shatrughna dragged her by the hair, and Bharata stopped him.
In the tradition
Later retellings often add that Manthara was influenced by the gods, who wanted the exile of Rama so that he could defeat Ravana. This is not part of Valmiki's main narrative.