He was coming to support Pandavas. Along the way, Duryodhana had created lavish facilities for eating and resting. Shalya was very impressed and was wondering who has created all these facilities. Duryodhana appears in front of him and says I have created all this for you. An impressed Shalya decides to change his allegiance to Kaurava. However, when he meets Pandavas later on, Bheema requests him to become the charioteer of Karna and insult Karna. This will bring down the confidence of Karna and will make it easier for Pandavas to defeat him. Shalya agrees. In effect, he would be pretending to be on the side of Kauravas, but will be supporting Pandavas.
He was coming to support Pandavas. Along the way, Duryodhana had created lavish facilities for eating and resting. Shalya was very impressed and was wondering who has created all these facilities. Duryodhana appears in front of him and says I have created all this for you. An impressed Shalya decides to change his allegiance to Kaurava. However, when he meets Pandavas later on, Bheema requests him to become the charioteer of Karna and insult Karna. This will bring down the confidence of Karna and will make it easier for Pandavas to defeat him. Shalya agrees. In effect, he would be pretending to be on the side of Kauravas, but will be supporting Pandavas.