The purpose of Lord Krishna’s birth was to restore the balance between the good and the evil and prevail peace on earth. He knew that for the well being of the Humans, the defeat of the kauravas was essential. The warriors on the side of the Kauravas during the war were not only the best but were very hard to kill, the list includes: Bhishma Pitamah, Guru Drona, Karna, Shalya Ashwathama( Guru Dorna’s son) , Shakuni (the strategist).
It was the modesty of Lord Krishna who believed that trickery and deception for the good of mankind was not evil.
Some of the tricks played by Lord Krishna were:
Bhishma Pitamah was an unparalled archer and Arjuna was not even a matter of worry for him. Bhishma had killed a lot of soldiers and was heavily damaging the Pandava Army. Lord Krishna knew that Bhishma would not attack a female warrior and so he informed Arjuna of his trick to send in Shikhandi in the war, who eventually killed him.
It was very well known that Guru Drona was not to be defeated by his students, because none of them were as great as him in the battlefield. So, Krishna devised a plan that Bheem will kill the elephant named “Asvathama” and the great Yudhistir, who known for his strict Adherence to Dharma, shouted “Aswathama is dead” during the battlefield and everybody knew that Yudhistir would never lie. Hearing about the demise of his son “Aswathama”, Guru Drona dropped his bow and arrow in shock and was immediately killed by Arjuna.
After the death of Abhimanyu, the next day Arjuna vowed to kill Jayadratha before sunset or he will burn himself to death in case of failure. The Kauravas made a shield around Jayadratha, which was impossible to break. So Lord Krishna requested Yogamaya, the goddess of illusions, to create an illusion of sunset.This made Jayadratha come out of the shield created by Kauravas and dared Arjuna that it was time for him to die. Yogamaya removed the illusion and sun came up again. Arjuna flung an arrow from his bow immediately and Jayadratha’s head dropped in his father’s lap.
Krishna knew that Arjuna’s rival ,Karna, had a powerful weapon that could easily kill Arjuna. To save his life, Krishna asked Ghatotkach to attack Duryodhan so severely that Karna is forced to use his weapon against him. During the war, Ghatotkach did as he was told, and that not only saved Arjuna’s life but also eventually led to killing of Karna by Arjuna.
It had become impossible to defeat Karna until he had weapons in his hands. Arjuna fired an arrow at the chariot of Karna on the guidance of Krishna which made Karna’s chariot get stuck deep in the earth. Karna got down from his chariot and Krishna immediately ordered Arjuna to kill him, arjuna fired an arrow cfrom his bow and beheaded Karna.