Who is Ambalika and ambika in the epic story of mahabharata ?

In the epic story of Mahabharata, Ambalika and Ambika are two sisters who played crucial roles in shaping the future of the Kuru dynasty.

Ambika was the daughter of King of Kashi, and she was chosen by Bhishma as a bride for Vichitravirya, the younger son of King Shantanu. However, on the day of the wedding, Vichitravirya died. After this incident, Ambika remained unmarried.

Ambalika, on the other hand, was the younger sister of Ambika. After the death of Vichitravirya, Queen Satyavati, the mother of Vichitravirya, requested Vyasa (the sage and father of Vichitravirya and half-brother of Satyavati) to father children with the two widowed sisters through a practice called Niyoga. However, Ambika and Ambalika were not pleased with the appearance of the sage, and it is said that Ambika closed her eyes out of fear when she saw Vyasa. As a result, her son, Dhritarashtra, was born blind.

Ambalika, too, was terrified by Vyasa's appearance but turned pale in fear. This resulted in her giving birth to Pandu, who had a pale complexion.

Thus, Ambika became the mother of Dhritarashtra, and Ambalika became the mother of Pandu, who later became the fathers of the Kauravas and Pandavas, respectively.