Here are a few more names of the most powerful characters from our mythology.
In Indian mythology, warriors were divided mainly into three segments, Rathi, Atirathi Maharathi, and Atimaharathi according to their powers. Warriors like Bhima, Duryodhana, and Yudhisthir were in the category of atirathi and Bhisma, Raavan, Karna, and Arjuna were Maharathis and there has been one character who was Atimharathi, the most powerful warrior among all warriors in Indian mythology barring Gods and Demi-Gods.
Ravana was the son of Rishi Visrva and Kekasih, the princess of Rakshas which makes him half Brahmin and half Rakshas. He got a boon from Lord Brahma that no one can defeat or kill him except the humans because according to Ravana, humans are not even worthy enough to fight with him.
Along with being a great warrior, he was a big devotee of Lord Shiva and a very learned person who knows the four Vedas. He was the king of Lanka, which was the most powerful and prosperous country of that era. Lord Vishnu had to take an avatar as a human to kill him as otherwise, it was impossible to kill him.
Karna was a kind of anti-hero character in Indian mythology whose life was full of many tragedies. He was the son of Lord Surya (The Sun God) and Kunti. Once Rishi Durvasa gave a boon to Kunti that she can evoke any Deva and bear a son from him. She tried the boon and evoked the Sun God and Sun God blessed her with a son. Because she was unmarried at that time, she had to leave Karna in river Ganga as a child before marriage was unacceptable then and would have brought dishonor to her and her family.
Karna was brought by his foster parents. He was born with golden armor and earrings and it was impossible to kill him. He learned archery from Lord Parshuram and was a rival of Arjuna in archery. He was humiliated all his life because of his status of being a lower caste, Duryodhana made him a king and because of this he was indebted to Duryodhana and fought from his side in the Kurukshetra war where he was killed by Arjuna when he was unarmed.
Meghnad the son of Ravana and Mandodri is the most powerful character in the whole of Indian mythology. He was the only character in Indian mythology who was the only one who had Pashupatastra and Vaishnavastra including Brahmastra, the most powerful weapons ever. He defeated the king of Devas, Lord Indra and that’s why he is also known as Indrajit, the one who defeated and captured Indra. He let go of Indra only when Lord Brahma gave him a boon that no one will ever be able to defeat him in a war, but before every battle, he needs to perform a 'yagna' for Parthyangira Devi.
He made both Rama and Laksmana unconscious who was saved only after the intervention of Garuda. He almost killed Lakshmana and Lord Hanuman saved him by bringing Sanjeevni booti. He killed more than half of the vanars in a single day and great warriors like Lord Rama, Lakshmana and Hanuman were unable to stop him. He was killed by Lakshmana later in the war by treachery as Hanuman and his army of vanars didn’t let him finish ‘yajna’ which would have made him undefeated.