Karna no longer exists as a distinct being. Let me explain. In the Swargarohanika Parva of the Mahabharata, Yudhishthira arrives in Devaloka in his own body (which he did by successfully going on the Swargarohini mountain path, unlike his brothers and Draupadi who fell off).

Understanding the Context

He is initially presented a false vision of the Pandavas, Karna, and Draupadi all residing in Asuraloka, but that was just a test to see if Yudhisthira was willing to reside in Asuraloka with his loved ones, which he ... O king! Vaikartana Karna was the only one who stood immobile like a mountain. Duryodhana, Karna and Shakuni Soubala were severely wounded in the field of battle, but kept fighting the gandharvas.

Key Insights

With a desire to kill Karna in battle, hundreds and thousands of gandharvas rushed collectively towards him. No. Karna did not play any game of dice with the wife of Duryodhana. Second of all Duryodhana's wives are not named in Mahabharata. None of them are called by their names.

Final Thoughts

The name Bhanumati is not mentioned in the Mahabharata. Duryodhana had at the very least two wives, one from Kasi and one from Kalinga. At Bhishma's deathbed he talks about how karna abducted a kasi princess for Duryodhana, and at the Shanti Parva, Narad muni mentions Karna's biography and narrates how Duryodhana abducted ... Looking at the answer that you accepted, the pashupatastra is never to be used against mortals, it will destroy the whole universe blah blah blah. Therefore, it is practically useless in the mahabharata war. One wonders why Arjuna even tried for it.

On the other hand I wonder how an immortal can be called an immortal if he/she can be slain. These divyastras have no logic.