The evil sins of Karna according to Bori Critical Edition.

Karna plotted to murder the Pandavas in their childhood, prior to the introduction of Kripa (by vaisampayana).
Quote:

"Then Duryodhana, Karna and Subala’s son Shakuni tried many other means to kill the Pandavas."

Analysis: Karna's name is clearly mentioned over here, separately from Duryodhana's and Sakuni's. So it was not Gandhari's son karna, Yuyutsu karna or a different karna etc. It was Radheya Karna. Some karna fans just deny this fact for some reason but karna's crime over here was that he wrongfully targetted the Pandavas (people who at this point in time never did anything bad to him, yet he still targetted them.
Source: Adi Parva Section 119

• Poisoning of Bhima

 This also proves that Karna was involved in the poisoning of Bhima (mentioned just a few lines before this incident).

Karna talks about the poisoning himself.

• Incident 1 (twelfth day)

Quote:

The Pandavas will remember the hardships from poisoning, arson, gambling and dwelling in the forest.38 It is my view that they will not retreat from the battle.

Analysis: This is not karna admitting his part/role in the incident but he was definitely involved and knows about this incident.

Source: Drona Parva Section 21

• Incident 2

Quote:

All our manliness has been rendered futile by fate. We have always endeavoured, but our valour has been unsuccessful. Whenever a man performs an act, but is not favoured by destiny, fate destroys all his exertions. A man with perseverance must do whatever he has to do and must not have doubts about the act. Success depends on destiny. O descendant of the Bharata lineage! The Parthas were deprived through deceit and the use of poison.42

Analysis:

Based on Karna's beliefs over here " must do whatever he had to do", key focus on the word "whatever" he was definitely a cheater, who would do anything to get rid of his adversary. So indirectly karna admitted that he poisoned bhima.

Source: Drona Parva Section 127

Screenshot:

• Karna conspired to kill the Pandavas after the defeat of Drupada and before the burning of the lac house.

Quote:

‘On seeing that Bhimasena had become extremely strong and Dhananjaya extremely skilled, the evil Duryodhana was tormented. Then, Vaikartana Karna and Subala’s son, Shakuni, tried to kill the Pandavas through various means. However, the Pandavas, slayers of enemies, discovered all of them. But because of Vidura’s advice, they refrained from revealing these plots.

Analysis: The "various means" that Karna and Sakuni (son of Subala) used in their attempts to kill the Pandavas, are described as "plots'.

• Definition of the word "plots" (from a google search)
• noun

Quote:

a plan made in secret by a group of people to do something illegal or harmful.

Analysis: Here it is described as illegal, and when someone is doing something "illegal" then they are attempting to do something unethical. So Karna was not ethical, he was a cheater and a coward.

• verb

Quote:

secretly make plans to carry out (an illegal or harmful action).

Analysis:

This means in secrecy, and it is basically the same definition as before for the noun. And what right did karna have to harm them (the pandavas) anyways? They were righteous people that never did anything bad to him.

Source (for the screenshot): Adi parva Section 129

• Karna was involved in a conspiracy to kill the Drupad his daughter's Swayamvara.

Quote:

‘When the king expressed his desire to give his daughter to that greatsouled Brahmana, all the assembled kings looked at each other and were filled with anger. The kings said, “We are assembled here and he passes us over like straw. He wishes to give Droupadi, supreme among women, to a Brahmana. This evil-hearted one does not respect us. Let us kill him. He does not deserve our respect or veneration because of qualities of age. On account of this, let us kill this wretch who insults kings and their sons.

1st Source: Adi parva Section 180
2nd Quote:

Seeing the Kshatriyas, with Karna leading them, furious to do battle, they fell upon them, like two elephants against hostile elephants. Eager to fight, those kings then said, “It is permissible to kill a Brahmana who is willing to fight.”

Analysis: The 1st quote very specifically says "the kings said', so all kings would include Karna. The 2nd quote has Karna leading the Kshatriyas to attack Drupad.
2nd Source: Adi parva section 181
And Arjuna having a bow like Gandiva does not matter because even supposed "gods" like Vishnu, Shiva, Krishna, Rama etc had the Saranga bow, Kodanda bow and Pinaka bow. Yet no one calls them "nothing" without these bows. So the bow theory is just a sad excuse to hide from the fact that Karna was defeated fair and square in battles.

• Karna offering his wives to foot soldiers of his enemy's army

Quote:

If the man who shows me Arjuna thinks that this is not enough, I will give him another boon that he will desire himself. I possess sons, wives and riches. If he desires these, I will again give them to him.

Screenshot:

Source: Chapter 1177(27)

Here are the opinions of ordinary/average Kshatriya male (in ancient india - your ancestors) on Karna's character.

This man has always been wicked. He bases himself on Duryodhana’s advice and is the root of all injury. Let us kill him.’ Thus conversing, the kshatriyas attacked.

As per them Karna was the main cause of the kurukshetra war.

Source: Chapter 1111(134)

Now regarding the house of lac, bori mahabharata does not have much references on karna's actions during that incident. But he was indeed a coward, a misogynist, a jealous person (who could not get over his failures). He shares a lady like a piece of biscuit, ran a human trafficking business, and gives his wives to his own enemy's servants. Shows how much he values his woman.

And he ran away from many fights. Even Draupadi's sons, and the armoured battalions of Matsya defeated him, a team of foot soldiers defeated karna too. He was just a useless character.

Some other crimes of karna

• Abduction of a kalinga princess, using force on her family and the maiden because she did not want Duryodhana.

Quote:

Protected by Karna, Duryodhana was assured. Bringing the maiden with them, they cheerfully returned to the city of Nagasahvya.”

Screenshot:

Analysis: Note that "all the kings" would include the princess's father. So Karna basically beat up a woman's father because his friend Duryodhana wanted her. And don't forget that the text says both of them brought the maiden with "them" meaning karna also touched the maiden and must have offended her.

Source: Santi Parva Section 4

• Slaughtering his own troops

Quote:

They abandoned Karna and Bhima and fled in all the directions, saying, ‘There is no doubt that, for the sake of the Parthas, the residents of heaven are confounding us, since the force of Karna and Bhima’s arrows are killing our troops.’ Having said this, the warriors on your side were afflicted by fear.

Screenshot:

Analysis: It's clearly written that karna killed his own troops. The troops that belonged to the side that he was fighting for. The Kauravas. Yet some karna fans will cry saying that the gods were confounding them, they should know it does not change the fact that karna killed his own soldiers. They forget about the "skin" lines too, and how the sindhu/kourava army ran away. These incidents were before and after what the troops said too, so he killed his army three times on the 14th day alone itself. He would be court martialed and imprisoned for such a war crime.

Source: Drona Parva Section 113

• Suggesting the disrobing of Draupadi

Quote:

On seeing Krishna look at her miserable husbands, Duhshasana dragged her with even greater force, so that she almost lost her senses. He repeatedly called her “slave” and laughed uproariously. Karna was delighted at these words and approved of them by laughing out loudly.

Analysis: Now don't say that the pandavas were just watching as helpless ducks, they all understood the truth that Yudhishthira had sent a messenger to Draupadi and that this was a part of his plan to get them freedom without breaking vows. Karna was totally out of line with his conduct in this incident.

Source: Sabha Parva Section 60

• Karna was a cheater, he being a human used "maya" to fight

Quote:

As he fought with Pandu’s son, the son of the suta used the maya of his weapons and severed his quivers and his bowstring with arrows that had drooping tufts.

Analysis: Perhaps karna had an identity crisis and wanted to ccopy the Rakshasas in their form of fighting. He knew he could not stand a chance against warrior like Bhima without the use of maya. Karna had no respect for ethics in war.

Source: Drona Parva Section 114

• Badmouthing the punjabi's (people of the country of five rivers

Quote:

You have been born in a wicked country and are evil in intelligence. You are inferior and the worst among kshatriyas. If you are a well-wisher, why are you frightening me about the two Krishnas, like an enemy? Today, I will be stationed in battle and either I will kill them, or they will kill me. I am not scared of the two Krishnas. I know my own strength. I will single-handedly slay one thousand Vasudevas and one hundred Phalgunas. O one who is born in a wicked country! Do not speak. Women, children, aged ones and those who have completed their studies often say something about the evil-souled ones from Madraka383 and it has become a universal saying.

Quote 2:

But this is not true of the Madras from the land of the five rivers. They are false in their tongues.

Screenshot (to prove that "Madra" is in modern-day Punjab):

Analysis: I wonder how the blood of Punjabis does not boil upon reading what karna said about their ancestors. Karna's views on the kingdoms of the indian sub-continent during the iron age were very disgusting barbaric views, akin to a terrorist's. Madra kingdom is in eastern punjab.

Source: Karna Parva (bori critical edition)

So 9-10 SINS OF KARNA.