The following is from a work-in-progress called The Mahabharata: a Book Report, in which I'm slowly reading through the Hindu epic poem The Mahabharata, and writing a book report on what I read.
Like a good king, Yudhisthira sought the counsel of other wise men, before deciding what to do. His friend Krsna told him of many kings and realms beyond his own, and explained some of the past and present conflicts among kings. It was like Game of Thrones--there was a vast and complicated world beyond the palace walls of the Pandavas.
Krsna spoke at length about the villainous king Jarasamdha, who recently conquered many lands and took several kings as prisoners. Jarasamdha planned to capture more kings and then sacrifice (i.e. ritualistically murder) them all! Krsna encouraged King Yudhisthira to rescue the captive kings and take down the evil Jarasamdha. Then, Yudhisthira would be worthy to be a great king among kings.