In the anticipation of a great war between the contenders of Hastinapura, a spree of alliance-making ensues across the continent. Krishna limits the exposure of the Yadava clans by assuming an active sort of neutrality, in which he shows himself to favor both factions. To the Pandavas, he offers his own services, albeit with the caveat that he shall not personally pick up arms for their cause. To the Kauravas, he offers an army with many warriors. In contrast, Krishna’s elder brother, Balarama, offers passive neutrality, excusing himself from the war games altogether.
The specific role that Krishna shall play during the war does not remain undecided for long. Arjuna expresses his desire that the Yadava king becomes his charioteer, a proposition that Krishna happily accepts.
Subsequently, Shalya, the king of Madra—and the brother of Nakula and Sehadeva’s mother, Madri—marches towards the Pandavas with his huge army, apparently to show his strength and to commit himself as their ally. But the facilities at every resting spot of his army are provided for by Duryodhana. Duryodhana does exceedingly well at pleasing this distant uncle of his. Out of a mixture of inebriation and gratitude, Shalya gets into an alliance with Duryodhana.
One expects Shalya’s about-turn to be a big blow to the Pandavas, but it does not turn out to be so. When the king of Madra finally meets Yudhisthira and details how he has already made a commitment to Duryodhana, the eldest Pandava tries to make his uncle work as their spy. Shalya is asked to become Karna’s charioteer and is charged with sapping Karna’s confidence with his words, something that he is to do at the right time, presumably when Karna and Arjuna engage in a decisive battle. Shalya, perhaps embarrassed by his absent-minded commitment to Duryodhana, leaps on to this opportunity to realign his loyalties.
The exchange between Yudhishthira and Shalya tells us how the pursuit of victory has become one without compunctions. It also tells us that, whatever the Pandavas’ achievements—rather, whatever be the belief in Bhima’s and Arjuna’s individual prowess—the brothers do not regard victory as a certainty.
That said, there is a difference between the Pandavas’ and the Kauravas’ approaches: while Duryodhana seeks hefty military contribution from his partners, Yudhisthira and his brothers are more focused on the minutiae, and appear to be trying to get into positions of advantage with respect to the one-on-one battles between major luminaries on either side. The Pandavas are not particularly keen to add a lot of foot soldiers to their army and seem to have the sense that the war will be decided by these key battles.
Duryodhana, on the other hand, repeatedly goes for brute force. Elated with how Krishna’s war contribution has been distributed, Duryodhana does not realize that his own allies will not be keen to engage Arjuna in a one-to-one battle now, for the fear that any incidental harm to Krishna will bring the combined wrath of the Yadava tribes on them.