I was checking out the legends associated with the Pitri Paksh or Shraadh rituals and it led me to the story of Karna which goes like this:
When the legendary donor Karna died in the epic Mahabharata war, his soul transcended to heaven, where he was offered gold and jewels as food. However, Karna needed real food to eat and asked Indra, the lord of heaven, the reason for serving gold as food. Indra told Karna that he had donated gold all his life, but had never donated food to his ancestors in Shraddha. Karna said that since he was unaware of his ancestors, he never donated anything in their memory. To make amends, Karna was permitted to return to earth for a 15–day period, so that he could perform Shraddha and donate food and water in their memory. This period is now known as Pitru Paksha.In some legends, Yama replaces Indra.
First of all, does that imply there were no Shraads performed before the Mahabharat times?
And secondly, being the son of Surya, which ancestors would Karna perform Shraadh for - if it is Kunti's ancestors, wouldn't other Pandavs perform ceremony for them anyways?