Karna is one of the central characters of the epic Mahabharata. He is counted as one of the maharathis who were there in the army. He was the son conceived by Kunti in curiosity to check the blessing given to her by Rishi Durvasa.
Maharani Kunti served Durvasa rishi with great care and attention and hence, won his heart. In return for her service, he blessed her with a boon that whosoever demigod she will call with this mantra, he is bound to appear before her and bless her.
Out of curiosity, she invoked Surya dev and he appeared before her. He asked her to ask for a boon to which she said that she was just testing. Since Surya was bound to give her a progeny, he gave her a son who was as brilliant as him.
Since Kunti was a maiden at that time, to avoid disrespect and dishonour, she took the child and rendered him afloat in the river. The child was received by the couple, Adiratha and Radha who nourished and fostered him nicely.
Since Adhirathi was the charioteer of Maharaj Dhritarashtra, the child became inclined to Kauravas and hence, ended up battling against his own five brothers. He was blessed with all nice qualities and was almost invincible due to the golden armor of Surya and the blessings given to him by Parashurama, his spiritual master.
He also received several curses from his master, a brahmin and mother earth which lead to his ultimate end. Karna was one of the greatest warriors, whose martial exploits are recorded in the epic, and the only warrior believed to be able to defeat mighty Arjuna in battle, an admiration expressed by Sri Krishna and Bhishma pitamah within the body of this work.
Karna is often quoted for his sacrifice, courage, charity, valour, and selflessness and hence got the name Danveer Karna.