Since Then: Sun and Ben didn't interact at all during her first stay on the island. After escaping though, she somehow concluded he was responsible for Jin's death. She sought out Widmore to ally against their enemy, and he sent her a gun so she could shoot him. She found Ben at the LA marina and aimed the gun at him, but he convinced her Jin was alive. Back on the island, Sun began tracking Ben, but instead of following him, she knocked him out with an oar. They traveled together for some time, and Sun reluctantly accepted him as an ally.
Since Then: The two interacted little initially because Sun pretended not to know English. When Sun lost her wedding ring though, Hurley helped her search for it, and the two made conversation about her life in Seoul. Later, when Sun was taking a pregnancy test, and Hurley was sneaking a chocolate bar, she and Hurley bumped into each other in the jungle, each with their own secret.
The two escaped the island together, and Hurley visited her in Korea after Ji-Yeon's birth, making him the only one of the Oceanic Six to come visit her. They returned to the Island on Ajira 316, but while Sun landed in 2007, Hurley traveled to the past. They reunited and embraced a week later.
Origin: Sun crushed eucalyptus for Shannon, Jack's patient, helping her where he had failed.
Since Then: Sun assisted Jack in another medical operation, when he treated Boone. Sun realized that Jack was willfully ignoring Boone's internal injuries and tried to convince him to stop treating him in vain. Jack also noted Sun's garden with approval, and offered seeds for it, via Kate. When Jin left the Island on a raft, he advised Sun to stay with Jack for safety. Later, Sun consulted Jack when she thought herself pregnant. When Jack returned from his time with the Others, Sun welcomed him back to the beach with a hug. And when the camp split up, Sun chose to stay with Jack.
The two escaped the Island together. They lost touch - Jack did not come to visit Sun's daughter - but Sun visited Los Angeles some years later. Her surveillancve of Ben meant keeping tabs on Jack as well, and the two met again at the Longbeach Marina when Sun planned to kill Ben. They together visited Mrs. Hawking, and Sun showed up the next day for Ajira FLight 316, to Jack's surprise. When the plane landed on the Island, Jack had vanished, but the two reunited a week later. Sun lost the power speak, and Jack diagnosed her with aphasia, and she agreed to stay with him because she trusted him. Jack managed to free her from a cage shortly afterward, and his advice on Widmore's submarine almost saved her life. Jin though convinced Jack to leave the two of them to die together.
Origin: Before meeting Jin, Sun was initially introduced to Jae Lee, the son of a wealthy hotelier, by a matchmaking scheme from their respective parents.
Since Then: The two hit it off, but Jae disappointed Sun with the news that he'd fallen in love with an American girl. Sun then met Jin and married him but began taking English lessons from Jae Lee. Before long, Jae Lee confessed feelings for her, and they began an affair. Sun's father discovered what was happening. Sun attended Jae Lee's funeral soon after.
Origin: Kate was attending Sun's garden with Sun and talking about herself thinking that Sun didn't understand English. When Sun gave a smirk, Kate claimed Sun understood her. Soon after Sun admitted to Kate about speaking English.
Since Then: Kate later convinced Sun to poison Jin to prevent him from going on the raft. However, Sun accidentally poisoned Michael instead. Kate and Sun had conversations about men and relationships such as in ...and Found when they found Sun's lost wedding ring. Sun confided in Kate when she believed herself pregnant. Kate helped Sun escape the island, though this meant leaving Jin behind to die on the freighter. Back in civilization, Sun returned to Korea while Kate's parole terms confined her to Los Angeles. They met again some years later when Sun came to LA on business. Kate stayed with her while she was fleeing a lawyer who was investigating her. Sun babysat Aaron and lent Kate a change of clothes.
Origin: Jin, the son of a rural fisherman, literally bumped into Sun, who is the daughter of powerful corporate CEO. The two instantly connected and started secretly dating.
Since Then: Jin proposed, and Mr. Paik granted permission, hiring Jin as a personal assistant. The two married, but jin's increasingly violent work and their inability to conceive drove them apart. The two traveled to Los Angeles via Sydney for Jin's business, and Sun planned to leave Jin at the airport, while Jin planned to stay in America with Sun, abandoning her father. Instead, they crashed on to the Island.
Jin acted heavily protective of Sun on the Island, attracting criticism from several survivors. Jin became briefly suspicious of Sun's relationship with Michael, who almost kissed Sun. Sun began rebelling slightly from Jin's control, and she eventually revealed to him that she'd learned English to leave him. Jin then prepared to leave her on a raft, but the two reconciled before he left. An attack destroyed the raft, convincing Sun that Jin had died, but Jin returned to camp, and the two conceived a child together. Sun eared the child could be Jae Lee's, and Juliet revealed these suspicions to Jin, but the couple made up again. They tried to escape the Island on the freighter, but it exploded, apparently killing Jin.
Sun lived alone in Korea for some years, raising their daughter and seeking vengeance against those she held responsible for Jin's death. When Ben told her Jin was still alive, she returned to the Island. The two reunited but died together soon after, Jin choosing to die with her when she became trapped in a sinking sub.
In their flash sideways, the two shared a loving but unmarried relationship, and Mr. Paik ordered Jin's death. But the two awoke during a sonogram of their daughter, and they moved on with their friends.
Origin: Ben sent Juliet to the camp identify and examine all pregnant women.
Since Then: Sun approached Juliet, demanding to know about the Island's effects on pregnant women. Huliet explained and examined Sun. The medical questions embarassed Sun, but she answered them, and revealed that she had slept with someone besides Jin. Juliet took Sun to the Staff station and performed a sonogram, and the news that the baby was Jin's but that the pregnancy could kill the mother and the fetus, made Sun cry with joy and sadness. When Sun became suspicious about their rescuers from the freighter, she decided to stay on the Island, which distressed Juliet. She revealed Sun's affair to Jin to eventually convince them to leave the island. She later made sure Jin and Sun were some of the first people to sail to the freighter for rescue. When the freighter exploded, she feared Sun dead, but Locke said she had somehow escaped, and Jin presumably later explained exactly what had happened.
After death, in a flash sideways, Juliet again performed a sonogram on Sun, waking up the couple. Their emotion and recognition confused her.
Origin: The two spent months on the island together, but Sun left before any encounter.
Since Then: When Sun returned, she saw the Man in Black, as Christian, in the old DHARMA processing center. He told her to wait for John Locke and returned shortly after - as John Locke. She followed him for some time because he claimed he knew how to reunite her with Jin. She eventually, however, learned that he was not Locke at all.
Sun entered the Temple while the monster was attacking and then left right after. Some days later, the Man in Black approached her in her garden, offering his hand and a new promise to bring her to Jin. She fled, not trusting him. When she and Jin were later together in a cage, the monster came to help break them out. Sun followed him to Widmore's submarine, where she dies, as he'd been planning.
In Sun's flash sideways, she caught sight of Locke when recovering consciousness and briefly mistook him for the Man in Black.
Origin: Michael stumbled upon Sun when she was bathing.
Since Then: Michael started leaving Walt with Sun. When Jin attacked him, Sun admitted to Michael that she knew English, and the two grew closer. The two almost kissed in the jungle once, but Vincent interrupted them. Michael later tried defending her from Jin, but she slapped him, taking her husband's side. They parted awkwardly when Michael boarded the raft.
When Michael returned to camp after his time with the tail section, Sun was the first person he saw. He reunited with her again after his time with the Others, hugging her and Jin. After he left the Island, Hurley presumably told her abouthis betrayal. The two met again weeks later aboard the freighter, and Michael congratulated Sun on her pregnancy.
Origin: Sun did not know Widmore until she left the Island, though coincidentally, she once used a pregnancy test that was made by Widmore Labs
Since Then: Though Jin supposedly died on Widmore's ship, Sun blamed Ben for his "death", and she sought out Widmore's help because they shared a common enemy. She first approached him openly on the street, and this audacity shocked the man. Widmore later had her held at London's Heathrow airport, where the two conspired to kill Ben. Once Sun reached Los Angeles, Widmore posted her several surveillance photos of Ben - and a gun.
Sun didn't end up killing Ben when she found out Jin was alive, and she instead traveled with him to the Island in 2007. Widmore ended up coming to the Island as well via a submarine, and he retrieved Sun's camera from her crashed plane. He later imprisoned Sun along with Jin and several followers of the Man in Black in cages, therefore, he was ignoring their earlier off-island partnership. Widmore was later killed by Ben at the Barracks while Sun died with her husband Jin on Widmore's submarine.