Karna being rescued by others against his enemies!

All right first things first. After reading this post you all will know how many times Karna had to be saved from his opponents, a third party had to interfere in his fights against his adversaries all the time. I am dividing this post into 3 parts. Before Kurukshetra war (BKW) and during Kurukshetra war (DKW). Lastly the names of the characters who saved Karna from his enemies.

1. Before Kurukshetra war
1. Before birth: Thereupon Kunti said, 'If, O dispeller of darkness, I obtain a son from thee, may he be furnished with a coat of mail and ear-rings, and may he be mighty-armed and endued with great strength!' Hearing these words of hers, Surya answered, 'O gentle maiden, thy son shall be mighty-armed and decked with ear-rings and a celestial coat of mail. And both his ear-rings and coat of mail will be made of Amrita, and his coat will also be invulnerable.' Kunti then said, 'If the excellent mail and ear-rings of the son thou wilt beget on me, be, indeed, made of Amrita, then, O god, O worshipful deity, let thy purpose be fulfilled! http://sacred-texts.com/hin/m03/m03305.htm - (Chapter Link) 
2. Adi Parva: And the clouds seemed to laugh on account of the rows of white cranes that were then on the wing. And seeing Indra thus viewing the arena from affection (for his son), the sun too dispersed the clouds from over his own offspring. And Phalguna remained deep hid under cover of the clouds, while Karna remained visible, being surrounded by the rays of the Sun. http://sacred-texts.com/hin/m01/m01139.htm - (Chapter Link) 
3. Sabha Parva: Then Duryodhana and Karna and Sakuni, the son of Suvala regarding Drona as their sole refuge, offered the kingdom to him. Drona then, addressing the envious and wrathful Duryodhana and Dussasana and Karna and all the Bharata, said, 'The Brahamanas p. 155 have said that the Pandavas being of celestial origin are incapable of being slain. The sons of Dhritarashtra, however, having, with all the kings, heartily and with reverence sought my protection, I shall look after them to the best of my power. Destiny is supreme, I cannot abandon them. The sons of Pandu, defeated at dice, are going into exile in pursuance of their promise. http://sacred-texts.com/hin/m02/m02079.htm - (Chapter Link)
1. For thy sake, O Duryodhana, that terrible season of destruction is almost come. Do without loss of time, what may be beneficial unto thee. Think not that everything hath been accomplished by sending the Pandavas into exile. This thy happiness will last for but a moment, even as in winter the shadow of the top of the palm tree resteth (for a short time) at its base. Perform various kinds of sacrifices, and enjoy, and give O Bharata, everything thou likest. On the fourteenth year hence, a great calamity will overwhelm thee.'" http://sacred-texts.com/hin/m02/m02079.htm - (Chapter Link)
2. Basically Karna had went with his friends to Drona's abode to seek his protection and support against the Pandavas.
4. Ghosh-yatra: It was thus that many thousands of Gandharvas, together attacking his car, broke it into minute fragments. And while his car was thus attacked, Karna leaped therefrom with sword and shield in hand, and mounting on Vikarna's car, urged the steeds for saving himself."http://www.sacred-texts.com/hin/m03/m03239.htm - (Chapter Link)
1. Over here Karna had to be rescued from the Gandharvas who threatened his life. Vikarna saved his life.
2. During Kurukshetra war
1. 12th day (Dronabhisheka)
1. Guru Drona, best friend Duryodhana, contemporary Jayadratha rescue Karna from Satyaki after his loss - And cutting off Karna's bow with a couple of well-shot shafts, he once more pierced Karna on the arms and the chest with three arrows. The king Duryodhana, and Drona and Jayadratha, rescued Karna from the Satyaki-ocean, as the former was about to sink into it. http://www.sacred-texts.com/hin/m07/m07030.htm - (Chapter Link)
2. 13th day (Abhimanyu-Badha)
1. Karna's younger brother rescues him from Abhimanyu - The son of Phalguna, however, received them fearlessly. Endued with great valour and courage, the latter then, in a moment, with only a single arrow, cut off Karna's bow and standard and caused them to drop down on the ground. Beholding Karna in such distress, his younger brother, drawing the bow with great force, speedily proceeded against the son of Subhadra. http://www.sacred-texts.com/hin/m07/m07037.htm - (Chapter Link)
2. Drona rescues Karna by telling him how to kill Abhimanyu - Karna, afflicted with the shafts of Arjuna's son, once more said unto Drona, 'Exceedingly afflicted with the shafts of Abhimanyu, I am staying in battle, only because (as a warrior) I should stay here. Indeed, the arrows of this south of great energy are exceedingly fierce. Terrible as they are and possessed of the energy of fire, these arrows are weakening my heart.' The preceptor then, slowly and with a smile, said unto Karna, 'Abhimanyu is young, his prowess is great. His coat of mail is impenetrable. This one's father had been taught by me the method of wearing defensive armour. This subjugator of hostile towns assuredly knoweth the entire science (of wearing armour). With shafts well shot, you can, however, cut off his bow, bow-string, the reins of his steeds, the steeds themselves, and two Parshni charioteers. O mighty bowman, O son of Radha, if competent, do this. Making him turn back from the fight (by this means), strike him then. With his bow in hand he is incapable of being vanquished by the very gods and the Asuras together. If you wish, deprive him of his car, and divest him of his bow.' http://www.sacred-texts.com/hin/m07/m07045.htm - (Chapter Link)
3. 14th day (Jayadratha Vadha)
1. Rescued against Bhima 
1. Karna runs away from Bhima seeking the protection of his son Vrishasena's chariot - Suddenly shrouded with shafts by that firm bowman, viz., Karna, the son of Pandu, smiling the while, cut off Karna's bow-string. And then with a broad-headed arrow, he despatched Karna's charioteer to the abode of Yama. And that mighty car-warrior, viz., Bhima, deprived the four steeds also of Karna of their lives. The mighty car-warrior Karna then speedily jumping down, O king, from his steedless car, mounted the car of Vrishasena. http://www.sacred-texts.com/hin/m07/m07125.htm - (Chapter Link)
2. Durjaya rescues Karna - Beholding Karna placed in the distressful plight, king Duryodhana, trembling with wrath, commended (his brother) Durjaya, saying, 'Go, O Durjaya! There the son of Pandu is about to devour the son of Radha! Slay that beardless Bhima soon, and infuse strength into Karna!' Thus addressed, the son Durjaya, saying unto Duryodhana, 'So be it', rushed towards Bhimasena engaged (with Karna) and covered him with arrows. And Durjaya struck Bhima with nine shafts, his steeds with eight, his driver with six, his standard with three, and once more Bhima himself with seven. http://www.sacred-texts.com/hin/m07/m07129.htm
3. As usual Durmukha another brother of Duryodhana has to come to karna's safety and rescue - Beholding that foremost of men, viz., the son of Adhiratha, deprived of his car, Duryodhana, O monarch, said unto (his brother) Durmukha, 'There, O Durmukha, the son of Radha hath been deprived of his car by Bhimasena. Furnish that foremost of men, that mighty car-warrior with a car.' Hearing these words of Duryodhana, thy son Durmukha, O Bharata, quickly proceeded towards Karna and covered Bhima with his shafts. http://www.sacred-texts.com/hin/m07/m07130.htm
4. 5 more brothers of Duryodhana rescue Karna - Beholding Karna defeated by Bhimasena, five of thy sons, those uterine brothers that were great bowmen, could not, O sire, brook it. They were Durmarshana and Duhsaha and Durmada and Durdhara and Jaya. Clad in beautiful mail, all of them rushed against the son of Pandu. http://www.sacred-texts.com/hin/m07/m07131.htm
5. Duryodhana's brothers are sent for Karna's protection - Shrouded with showers of shafts shot from Bhimasena's bow, Karna once more turned his back upon Bhimasena. Beholding the Suta's son turn back and flying away on foot, covered all over with the arrows of Kunti's son, Duryodhana said, 'Go ye quickly from all sides towards the car of Radha's son.' 'Then, O king, thy sons, hearing these words of their brother that were to them a surprise, rushed towards the son of Pandu for battle, shooting showers of shafts. http://www.sacred-texts.com/hin/m07/m07132.htm - (Chapter Link)
6. Karna once again needs the safety of protection from his best friend Duryodhana's brothers - When that fierce uproar, making the hair stand on end rose, thy son Duryodhana, O king, quickly said unto all the kings and princes and particularly his uterine brothers, these words, 'Blessed be ye, proceed towards Karna for rescuing him from Vrikodara, else the shafts shot from Bhima's bow will slay the son of Radha. Ye mighty bowmen, strive ye to protect the Suta's son.' Thus commanded by Duryodhana, seven of his uterine brothers, O sire, rushing in wrath towards Bhimasena, encompassed him on all sides. Approaching the son of Kunti they covered him with showers of arrows, like clouds pouring torrents of rain on the mountain-breast in the season of rains. Excited with wrath, those seven great car-warriors began to afflict Bhimasena, O king, like the seven planets afflicting the moon at the hour of the universal dissolution. http://www.sacred-texts.com/hin/m07/m07133.htm - (Chapter Link)
2. Rescued Against Arjuna 
1. Aswathamman (Drona's son) saves Karna from being killed by Arjuna - Cutting off his bow, that hero, viz., Dhananjaya, the son of Pritha, quickly pierced Karna in the centre of the chest with nine arrows, Then Dhananjaya, with great speed at a time, when speed was necessary shot in that battle a shaft of solar effulgence for the destruction of Karna. Drona's son, however, with a crescent-shaped arrow, cut off that shaft as it coursed impetuously (towards Karna). http://www.sacred-texts.com/hin/m07/m07141.htm - (Chapter Link)
2. Aswathamman saves Karna again - And he also felled with a broad-headed arrow, Karna's charioteer from his niche in the car. And he covered Karna himself with clouds of shafts in the very sight of thy son. Thus shrouded with arrows the steedless and driverless Karna, stupefied by that arrowy shower, knew not what to do.Beholding him made carless, Aswatthaman, O king, caused him to ride on his car, and continued to fight with Arjuna. http://www.sacred-texts.com/hin/m07/m07141.htm - (Chapter Link)
3. Rescued against Satyaki
1. Vrishasena, Salya, Aswathamman save Karna again - And with his keen shafts, he slew the four steeds, white in hue, of Adhiratha's son. And then cutting into a hundred fragments the standard of Karna with a hundred arrows, that bull among men made Karna carless in the very sight of thy son. Then all thy warriors, O king, became cheerless. Then Vrishasena, the son of Karna, and Salya, the ruler of the Madras, and Drona's son, encompassed the grandson of Sini from all sides. http://www.sacred-texts.com/hin/m07/m07143.htm - (Chapter Link)
2. Dussassana and more Kaurava brothers save Karna from Satyaki - After Karna hath been made carless, thy brave sons, headed by Duhsasana, O king, were not slain by the self-restrained Satyaki because the latter wished not to falsify the vow made by Bhimasena. http://www.sacred-texts.com/hin/m07/m07143.htm - (Chapter Link)
3. Kritavarman is also included in the list - Although all those warriors headed by Karna made strong efforts for slaying Satyaki, yet those foremost of car-warriors, failed to slay him. Drona's son and Kritavarman and other mighty car-warriors, as also hundreds of foremost Kshatriyas, were all vanquished by Satyaki with only one bow. http://www.sacred-texts.com/hin/m07/m07143.htm - (Chapter Link)
4. Duryodhana saves Karna from Satyaki - Karna also, O king, pierced by Satwata with his arrows and exceedingly weakened ascended the car of Duryodhana, sighing deeply, remembering his friendship for thy son from his childhood and having striven to realise the promise he had made about the bestowal of sovereignty on Duryodhana. http://www.sacred-texts.com/hin/m07/m07143.htm - (Chapter Link)
5. Kurus got a new chariot for Karna so it can be his rescuer - A new car was brought for Karna also, O king, unto which were yoked four steeds of the best breed that were decked in trappings of gold and white as conchs or milk. Its kaksha and standard were made of gold. Furnished with banners and machines, that foremost of cars had an excellent driver. And it was furnished with a profusion of weapons of every kind. Mounting on that car, Karna also rushed against his foes. http://www.sacred-texts.com/hin/m07/m07143.htm - (Chapter Link)
4. 15th day (Ghatotkaca Badha)
1. Sakuni saved Karna from Bhima's dart - Then Karna hurled at the son of Pandu, a dart decked with gold. The Pandava, however, smiling the while, seized with his hand that dart. And the invincible Vrikodara in that battle hurled that very dart back at Karna. Then Sakuni, with a shaft that had drunk oil, cut off that dart as it coursed towards Karna. http://www.sacred-texts.com/hin/m07/m07151.htm - (Chapter Link)
2. Karna took shelter under Kripa's car (chariot) after losing badly to Arjuna - And that scorcher of foes also cut off from the trunk the head of Karna's driver.Then, the son of Pandu and Pritha pierced the bowless, the steedless, and the driverless Karna with four shafts. Then that bull among men Karna, afflicted with those shafts, specially jumping down from that steedless car, mounted upon that of Kripa. http://www.sacred-texts.com/hin/m07/m07155.htm - (Chapter Link)
3. 6 car warriors had to save Karna from Dhrishtadyumna - Once again, piercing all those warriors with keen shafts, that hero, with some broad-headed shafts, cut off the bow of Radha's son, that warrior conversant with all modes of warfare. Karna could not book that cutting off of his bow, like a fierce lion incapable of brooking the cutting off of his tail. Taking up another bow, Karna, with eyes red in rage, and breathing hard, covered mighty Dhrishtadyumna with clouds of arrows. Beholding Karna excited with rage, those heroes, viz., those six bulls among car-warriors, quickly encompassed the prince of the Panchalas from desire of slaying him. Seeing the latter in front of those six foremost warriors of thy side, all thy troops, O lord, regarded him to be already within the jaws of the Destroyer. http://www.sacred-texts.com/hin/m07/m07167.htm
5. 16th day (Karna Parva)
1. This happened on the first day of Karna being General. Several aitrathas of the Kaurava/Kuru army came to Karna's rescue against Satyaki - That bull of Sini's race also, in that battle, then quickly shrouded that foremost of men, with his car and steeds and driver, with diverse kinds of shafts terrible as the poison of the snake. Then many Atirathas belonging to thy army, accompanied by elephants and cars and foot-soldiers, quickly approached that bull among car-warriors, viz., Vasusena, when they beheld the latter deeply afflicted with the shafts of that foremost hero of Sini's race. http://www.sacred-texts.com/hin/m08/m08030.htm - (Chapter Link) 
1. They beheld Karna afflicted and wounded he lost to Satyaki he was in great danger.
6. 17th day (Karna Vadha)
1. Pouring upon him diverse kinds of weapons and thick showers of arrows, they began to afflict him like the clouds afflicting the mountain breast in the season of rains. Desirous of rescuing their father, the sons of Karna, all of whom were effectual smiters, and many other heroes, O king, of thy army, resisted those (Pandava) heroes. http://www.sacred-texts.com/hin/m08/m08048.htm - (Chapter Link) 
2. Struck by Bhimasena, O perpetuator of Kuru's race, the Suta's son, that commander (of thy forces), sat down senseless on the terrace of his car. The ruler of the Madras then, beholding the Suta's son deprived of his senses, bore that ornament of battle away on his car, from that fight. http://www.sacred-texts.com/hin/m08/m08050.htm - (Chapter Link)
3. Duryodhana sends another 20 of his brothers to rescue the defeated Karna from Bhima - 'Beholding Radha's son of the Suta caste turned back from the fight in that great battle, thy son, O monarch, addressed his uterine brothers, saying, "Go ye quickly, blessed be ye, and protect the son of Radha who is plunged into that fathomless ocean of calamity represented by the fear of Bhimasena." Thus commanded by the king, those princes, excited with wrath and desirous of slaying Bhimasena, rushed towards him like insects towards a blazing fire. They were Srutarvan and Durddhara and Kratha and Vivitsu and Vikata and Soma, and Nishangin and Kavashin and Pasin and Nanda and Upanandaka, and Duspradharsha and Suvahu and Vatavega and Suvarchasas, and Dhanurgraha and Durmada and Jalasandha and Sala and Saha. Surrounded by a large car-force, those princes, endued with great energy and might, approached Bhimasena and encompassed him on all sides. http://sacred-texts.com/hin/m08/m08051.htm
3. List of people who saved Karna.
1. Kaurava brothers (all in all 40 Kaurava brothers protected Karna)
1. 14th day (20 of them wasted their lives saving someone like Karna)
1. Previous sections
1. Durmukha
2. Durjaya
2. Section 131 
1. Durmarshana
2. Duhsaha
3. Durmada
4. Durdhara
5. Jaya.
3. Section 132 
1. Chitra
2. Upachitra
3. Charuchitra
4. Sarasan
5. Chitrayudha
6. Chitravarman
4. Section 133
1. Satrunjaya
2. Satrusaha
3. Chitra
4. Chitrayudha
5. Dridha
6. Chitrasena
7. Vikarna (also during ghosh-yatra)
2. 17th day (another 20 of them went all together to protect Karna after he was knocked into a coma by Bhima) Karna Parva Section 51 you can find them all.
1. Srutarvan
2. Durddhara
3. Kratha
4. Vivitsu
5. Vikata
6. Soma
7. Nishangin
8. Kavashin
9. Pasin
10. Nanda
11. Upanandaka
12. Duspradharsha
13. Suvahu
14. Vatavega
15. Suvarchasas
16. Dhanurgraha
17. Durmada
18. Jalasandha
19. Sala
20. Saha.
2. Not Kaurava brothers
1. Vrishasena (14th day against Bhima and Satyaki)
2. Other sons of Karna (against Pandava warriors on the 17th day)
3. Guru Drona (against Satyaki on the 12th day, also promised him protection pre kurukshetra war and he saved him from Abhimanyu too)
4. Shalya (against Satyaki on 14th day, against Bhima on the 17th day)
5. Kritavarman (against Satyaki on 14th day)
6. Jayadratha (against Satyaki on the 12th day)
7. Aswathamman (against Satyaki on 14th day, against Arjuna 2 times the same day)
8. Duryodhana (against Satyaki on 14th day and the 12th day too against the same warrior)
9. Dussassana another Kaurava brother but has more importance (saved Karna from Satyaki on the 14th day)
10. Sakuni (against Bhima on the 15th day)
11. Atirathas of the army (16th day)
12. Surya (protected Karna from Indra during Adi Parva also agreed to give him the coat of mail)
13. Kunti (she plotted to give him a coat of mail furnished with amrita before birth)
14. Karna's nameless younger foster brother (from Abhimanyu on the 13th day)

Karna pretty much always needed protection. No such warrior exists who had to be rescued and saved as much as Karna was. The burden of so many corpses of the brothers of Duryodhana rest on karna's soldiers to be honest.
LIFE OF KARNA, MERCY OF HIS ENEMY. Mercy of Arjuna.