- The most destructive warrior in Kurukshetra war since he killed seven Akshauhinis of Kourava soilders on the 14th day.
- He defeated the foremost Kourava warriors Bhishma, Drona, Karna and Ashwatthama multiple times.
- He killed powerful Kourava warriors like Bhagadatta, Jayadratha, Karna and Susharma.
- He killed the entire Samsaptaka army which belonged to the Trigarta chief Susharma.
- He fought powerfully with Drona on the 15th day and countered all the powerful celestial weapons fired by the veteran warrior on that day.
- He defeated Bhima and Satyaki more number of times than those two warriors had defeated him in the war. He defeated those two warriors separately at least nine times.
- He caught the powerful wheel of Lord Shiva known as Asani with his bare hands which was hurled by Ghatotkacha.
- He killed Ghatotkacha with the spear known as Vasavi Shakti otherwise the demon would have single-handedly wiped out the Kourava army.
- He was the originator of Bhargavastra the only weapon which Arjuna failed to counter in Kurukshetra war.
- He destroyed the indestructible diadem of Arjuna which was revered by deities like Varuna, Kubera and Lord Shiva.
- He defeated powerful Pandava warriors like Bhima, Satyaki, Dhristadyumna and Shikhandi multiple times.
- He single-handedly resisted the powerful demons of the Pandava army when they attacked for the first time on the 14th night.
- He was a possessor of tremendous destructive potential since he killed one Akshauhini of demons on the 14th night and another Akshauhini of Pandava soilders on the 15th day.
- He invoked Lord Vishnu’s all-powerful weapon known as Narayanastra and forced the entire Pandava army to surrender in the battle.
- He became absolutely invincible when Lord Shiva entered his body on the 18th night. Blessed by the deity, he single-handedly decimated the Pandava warriors who survived the carnage in the war.
- He killed ninety-eight of the Kourava brothers in archery duels.
- He brought down Duhshasana with a large sword and Duryodhana in a mace fight.
- He defeated Karna five times on the 14th day and once on the 17th day.
- He broke Drona’s chariot with a large mace on the 14th day and forced the veteran warrior to retreat from the battle.
- He single-handedly killed one Akshauhini of Kourava soilders on the 18th day.
- He overpowered Arjuna twice on the 14th day.
- He defeated powerful Pandava warriors like Bhima, Satyaki, Dhristadyumna and Shikhandi.
- He constructed the complex defensive war formation known as Chakra Vyuha on the 13th day which was responsible for the death of Abhimanyu.
- He killed more than two Akshauhinis of Pandava soilders during his term as the commander of the Kourava army.
- He fought fiercely on the 15th day and became unassailable to all the Pandava warriors. An unfair strategy was deployed by the Pandava brothers to bring him down on that day.
- He defeated Arjuna on the 2nd day of the war.
- He single-handedly resisted a group attack of all the Pandava brothers on the 7th day.
- He killed ten thousand Pandava warriors per day during his term as the commander of the Kourava army.
- He killed one million foot soilders of the Pandava army in the war.
- He fought fiercely to such an extent which provoked Lord Krishna to break the vow of being weaponless in Kurukshetra war.
- His seventh place in the ranking is justifiable. He performed incredible feats on the 1st day and the 13th day of the war. He didn’t perform successively throughout all the thirteen days he fought in the war. The previous six warriors in the ranking performed equally throughout all the days they fought in the war.
- He destroyed the flagstaff and killed the four horses of Bhishma’s chariot on the 1st day.
- He defeated foremost Kourava warriors like Drona, Kripa, Shalya and Ashwatthama on the 13th day.
- He defeated Karna thrice on the 13th day and killed all the six counsellors of the warrior.
- It took a combined group attack of Drona, Karna, Kripa, Ashwatthama and Kritavarma to bring him down in the battle. He was ultimately killed by Duhshasana’s son in a mace fight.
- He was considered to be the most skilled archer after Arjuna in the Pandava army.
- He defeated Karna four times in the war.
- He is remembered for the incredible feats he performed on the 14th day since he single-handedly defeated all the forces of the Kourava army on that day.
- He defeated foremost Kourava warriors like Drona, Kripa, Shalya and Ashwatthama on the 14th day.
- He killed the demon Alambusha who terrified the Pandava army with occult illusions.
- He was the greatest warrior among the warriors of his era who fought stationed on the back of elephants.
- He fought powerfully with Ghatotkacha on the 4th day of the war.
- He defeated Bhima in a battle on the 12th day.
- He hurled eight javelins and displaced the golden diadem over Arjuna’s head. Adjusting the diadem, Arjuna resumed to fight with him in the battle.
- He fired a lethal weapon known as Vaishnavastra to kill Arjuna in the battle. However Lord Krishna who was Arjuna’s charioteer consumed the energy of the weapon. Upon reaching Lord Krishna’s neck, Vaishnavastra turned into a garland of flowers. He was perplexed on witnessing the miraculous feat and resumed to fight with Arjuna. He was ultimately brought down by Arjuna after a fierce battle.
- He created powerful demons known as Paulomas and Yatudhanas with his occult illusions for the destruction of the Kourava soilders.
- He fought to such an extent on the 14th night that even Drona was unable to withstand his prowess in the battle.
- He is remembered for the epic fight he put up with Karna on the 14th night.
- He decimated the Kourava soilders with great prowess which provoked Karna to invoke the powerful spear called Vasavi Shakti.
- He was eventually killed by the spear hurled by Karna. When he fell down, he assumed a gigantic form and crushed one full Akshauhini of Kourava soilders to death in the battle.
This answer is based on BORI Critical Edition which is the authoritative version of Mahabharata.
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