The sister of Vasudeva (Krishna), begot by Arjuna and therefore he was the grandson of Pandu. Five sons were born to the five Pandavas by Draupadi, the daughter of Panchala.
स्वस्त्रीयो वासुदेवस्य पौत्रः पाण्डोर्महात्मनः। पाण्डवेभ्यो हि पाञ्चाल्यां द्रौपद्यां पञ्च जज्ञिरे॥