Karna undoubtedly was amongst important characters of ancient and great hindu epic "Mahabharat".
As we know that Karna was biological son of "Surya" and "Kunti". He was raised by Adhirath the royal charioteer of Hastinapore and his wife Radha as Kunti being an unwed mother, had to abandon baby Karna to avoid social stigma.
I come across something amazing while studying origins of the characters of Mahabharat in Skandh Puraan , I would like to share the information with all Karna fans. I hope this new piece of information will make you aware about unheard story of Karna and Shanidev.
Surya is one among 11 Adityas and son of Sage Kashyap and Aditi is an important deity. Surya got married to Sanjya [ also called Sangya/Sanjana] daughter of Demigod Architect Vishwakarma.
Sanja bore two sons , Shani , Yama and one daughter Yamuna [ who later became river] , thereafter she couldn't bear radiance of Surya and went for penance , while leaving for penance she created her image from shadow and instructed her to look after her husband [Surya] and children in her absence. Chhaya gave birth to Tapti[ who later became river] and Savarni Manu [ The first human ]. Initially Chhaya looked after and loved Sanja's children as her own but later when she given birth to her own children , she started being partial. Shani being eldest of his siblings was very stubborn kid , he got agitated by partial attitude of Chhaya towards him and his siblings [Yama and Yamuna]. On seeing his mother holding young manu in her arms , Shani got jealous of his brother manu and tried to pull him down. Chaya scolded Shani and asked him to behave , and in a fit of anger he raised his feets to hit his mother. Chhaya got furious of the actions of Shani and immidiately cursed him to be born as mortal human , and suffer for his karma in his life in Dwapaar Yuga. She said since you tried to pull your younger brother from my arm out of jealously and just to seek my attention may you be deserted by your human mother and be alienated from your siblings. You are so proud to be son of Powerful Devtaa , may you be born to unwed woman ,face public disgrace , suffer misfortune , your human siblings unaware of your identity will hate you and never respect you , since you are jealous of your younger brother Manu.
Shani was shocked by the curse and cried , ran to his father and narrated him the whole incident sobbing complaining that "Mother doesn't loves me neither she treats us equally , so I tried to hit her in anger it was my mistake , mother got angry at this and has cursed me. Please forgive me and free me from mothers' curse"
Surya replied to Shani that a mother would never curse her child despite of 1000 crimes and that he cannot undo the curse of Mother but in his next birth as human, he will be fathered by Surya himself , he will retain some of his devta like attributes in his human incarnation but will suffer a lot , has to face condemnation and bad luck through out his life and will be liberated of Manushya Yoni by 8th avtara of Lord Vishnu.
Source : Kashi Section , Skandha Puraan
website:http://thekarna.wordpress.com/2010/04/20/karna-a-cursed-demigod-in-human-avtar/