Lord Krishna's father Vasudeva was from Yadu dynasty. Balarama and Subhadra are also his children.
Kunti Devi is the mother of Karna, Yudhishthura, Bhima and Arjuna, who are collectively known as the Pandavas. Additionally, she is the aunt of Lord Krishna.
Bhima was strong by birth as he was born as an incarnation of Lord Vayu. During the battle of Kurukshetra, Bhimasena killed all one hundred Kauravas.
Bhishma pledges to remain unmarried to honor his father Shantanu's marriage. In return, Shantanu offers the gift of being able to choose the time of one's own death to Bhishma for his sacrifice.