Who is Madri?

The second queen

Madri was a princess of Madra and the sister of its king, Shalya. Bhishma arranged her marriage to Pandu, and she joined Kunti as his second queen. When Pandu gave up his throne after a sage’s curse, Madri went with him and Kunti into the forest.

The twins

Kunti had a mantra that could call the gods. After she had three sons, she shared it with Madri. Madri called the twin Ashvin gods, the healers of heaven, and gave birth to twins: Nakula and Sahadeva.

How Madri’s story ends (spoilers)

One spring, Pandu saw Madri alone by a stream and forgot the curse that hung over him. He died in her arms. Madri, feeling the death was her doing, chose to follow her husband onto his funeral fire. Before she did, she asked Kunti to raise her sons as her own. Kunti did, and the twins never knew any difference.

Her brother Shalya would later be tricked into fighting for the Kauravas, against his own nephews.