Later after Pandavas were in exile, Karna took up the task of establishing Duryodhana as the Emperor of the world. Karna embarks upon a worldwide military campaign, otherwise called Digvijaya Yatra, conquering all kings in every direction in order to subjugate kings, impose Duryodhana's imperial authority over them and establish Duryodhana as the emperor of the world. He commanded army that marched to different parts of the world to subjugate kings and made them swear allegiance to Duryodhana, the king of Hastinapur or else die in battle. In this military adventure, Karna waged wars all over the world and made submission of entire kingdoms in the world. He started Digvijaya Yatra having war with Panchala, defeating king Drupada and the kings under him. Then going to the north he defeated all the sovereigns of that quarter, defeated king Bhagadatta. And ranging all sides, he conquered and brought under subjection all the kings inhabiting the Himalayas and made them pay dues. Then descending from the mountain and he went to the east, he reduced the Angas, the Bangas, the Kalingas, the Mandikas, the Magadhas, the Karkakhandas, and also included with them the Avasiras, the Yodhyans, and the Ahikshatras. Having thus conquered the eastern quarter Karna went to Batsa-bhumi. Karna defeated Batsa-bhumi, Kevali, Mrittikavati, Mohana, Patrana, Tripura, Kosala and compelled all of them to pay tribute. Then going to the south, Karna defeated all the very powerful charioteers of that quarter and in Dakshinatya, Karna defeated Rukmi. After this Karna went to Pandya and the mountain Sri. And by fighting, he made Karala, King Nila of Mahismati, Venudari's son, and other kings living in the southern direction pay tribute. Then going to Dhristaketu of Chedi Kingdom, Karna defeated him and defeated all the neighbouring rulers. Then Karna defeated the Avantis and conquered the Vrishnis. Thus Karna conquered the entire west quadrant. He then further travelled west outside the land mass of Bharata Kingdom and made all the Yavana and Varvara kings pay tribute to Hastinapura and Duryodhana. And having conquered the entire earth i.e. east, west, north and south directions, Karna without any aid brought under subjection all the nations of the Mlecchas, the mountaineers, the Bhadras, the Rohitakas, the Agneyas and the Malavas. Having thus conquered and brought under his subjection the entire world, Karna came back to Hastinapura with immense wealth and power the world had never witnessed before.[2][16][17] King Dhritarashtra praised Karna, comparing him favourably to those like Bhishma and Drona, who had never returned such tribute. Having thus, Karna in a short time conquered the entire world with all the mountains, forests, skies, oceans, fields, cities and all the islands. Karna thus brought the entire monarchs of the world under subjection and gained imperishable wealth. King Dhritarashtra with Gandhari loved Karna even more than their children. Bringing tribute and allegiance from all the world's kings, Karna helped Duryodhana to perform the Vaishnava yagna to please Vishnu and crown Duryodhana as "Emperor of the World", as Yudhisthira did with the Rajasuya Yagna. No person in the entire universe, except Lord Vishnu and Indrajit, the son of Ravana in ancient times performed this Vaishnava sacrifice before. Duryodhana thus become the most powerful and the most wealthiest man in the world. Duryodhana even made plans and preparations to conquer Indra, the lord of the heavens and the father of Arjuna with the help of Karna in order to become the sovereign ruler of both heaven and earth.[18]
Karnan is so skill full that even using nagasthiram he can destroy the universe. He couldn't use brahmasthira at the end because of his gurus sabam thinking he wasn't Brahmin but he actually is kuntis son and Brahmin.sage giving bane foolish wrongly