Warning: Includes SPOILERS for The Last of Us season 2, episode 5!

Ellie's immunity is a significant plot point in Ellie's immunity is no longer the main subject or goal, it's still a topic of grave importance, as Ellie is the hypothetical difference between the post-apocalyptic world of The Last of Us and a return to structured civilization.

The commune in Jackson, Wyoming, seems to be one of the only safe havens left in the US, but word of Ellie's immunity could disrupt even the most sophisticated society at this stage. Particularly for the older survivors, Ellie would be the key to what they lost, and people would vie for control over her. That's why keeping her immunity a secret is so critical, and this has played a role in The Last of Us throughout season 2, particularly in episode 5's ending, in Ellie and Nora's climactic confrontation. There are several characters who know the secret, alive or dead.

7 Marlene

Marlene Hired Joel To Smuggle Ellie

Marlene was a prominent character in The Last of Us season 1, as she's the member of the Fireflies who tasks Joel with bringing Ellie to the hospital in Salt Lake City. The Fireflies were wrapped up in a devastating conflict with FEDRA in the Boston Quarantine Zone, making it vital for her to get Ellie away from the ongoing war. We saw Marlene task Joel and Tess with the mission in the show's opening episode, and she for the violent season 1 finale.

Marlene was the final character Joel killed in The Last of Us season 1, ensuring that she wouldn't be able to return for Ellie again.

When Marlene entrusted Joel with bringing Ellie across the country, she failed to anticipate that a bond would form between the pair. Marlene revealed that the only way for the vaccine to be made was for Ellie to die, setting Joel off on his rampage. Marlene was the final character Joel killed in The Last of Us season 1, ensuring that she wouldn't be able to return for Ellie again. She died with the secret, though season 2 shows that rumors continued to spread of Ellie's existence.

6 Joel

Joel Learned Of Ellie's Immunity After Taking The Job

Joel Miller was a black market smuggler in the Boston Quarantine Zone, making him an ally to Marlene and the Fireflies. When he first accepted the job of smuggling Ellie, he wasn't fully aware of her immunity. It wasn't until both she and Tess were bitten by Infected that he was able to realize that Ellie's claims were true, and that she was truly immune. Of course, Joel and Ellie went on to form a beautiful yet complicated relationship as adoptive father and daughter.

After Joel massacred everyone, including Abby's father, in the hospital in Salt Lake City, he and Ellie fled, believing they could keep her secret and return to Joel's brother, Tommy, in Jackson. While the Fireflies never pursued Ellie, the event still came back to haunt them, as Abby arrived in Jackson to kill Joel, taking revenge on him for killing her father. Ellie witnessed Joel's death without any of the former Fireflies realizing that she was the one their organization was destroyed for.

5 Tess

Tess Convinced Joel To Take Ellie Across The Country

Tess was Joel's partner, and the two of them lived together in the Boston Quarantine Zone prior to taking on the Ellie mission. Tess, Joel, and Ellie set out together, but she wasn't long for the job, sacrificing herself after being infected by a Clicker in just the show's second episode. Tess lit herself and a mass of Infected on fire so Joel and Ellie could continue onward, knowing she was dead already from being bitten.

While Joel was initially abrasive towards Ellie, Tess was more willing to believe that she was immune and that there might still be hope for a cure. If not for Tess, Joel might not have been willing to bring Ellie across such a distance. She was integral to the journey, even though she died so early on.

4 Tommy

Joel Told Tommy About His Mission In Season 1

After finally reuniting with Tommy in Jackson during The Last of Us season 1, Joel caught his brother up on Ellie and his assignment. Joel didn't reveal the information immediately, however, as the two had years of complicated feelings between them. They argued at first over the different places their lives had taken them, but the two brothers quickly made up and, in a rare moment of vulnerability at this point in Joel's life, he revealed that Ellie was immune.

As of now, in The Last of Us season 2, Tommy is still alive and is keeping Ellie's secret. He's actively involved in Jackson's council, and there's no one in the town who could make a serious effort to develop a cure. Not to mention, Tommy is essentially Ellie's uncle, and the games and show demonstrate that they share a close bond of their own, having spent five years living in proximity between seasons. If it meant Ellie's death to make a vaccine, he would surely protect her, just as Joel protected the secret.

3 Dina

Dina Almost Shot Ellie Before Listening To Her

Dina is Ellie's new love interest in The Last of Us season 2, and episode 4's ending saw Ellie reveal to her that she's immune. We saw Ellie having to cover up an Infected wound in season 2's premiere by cutting herself, and she burned herself to hide her original bite scars. She was forced to keep her immunity a secret even from friends like Dina and Jesse, but when she was bitten again in episode 4, she revealed it to Dina as a last resort, lest she be shot.

There aren't many people Ellie could trust to this degree, but Dina is one of them.

Dina was justifiably hesitant to trust Ellie's declaration that she was immune. Ellie tied herself to a chair overnight to prove that she wouldn't turn into one of the Infected, then explained herself in more detail. Dina feels a great deal of affection for Ellie, and she proved her willingness to protect the secret, even lying to Jesse upon his return in episode 5. There aren't many people Ellie could trust to this degree, but Dina is one of them.

2 Nora

Nora Discovered Ellie's Immunity From The Spores

The Last of Us season 2, episode 5, introduced the toxic spores, which can spread the Cordyceps Infection through the air. This was a common obstacle in the video games, forcing characters to wear gas masks. However, this was the first time they were used in the TV series, establishing the precedent for Nora and Ellie's showdown in the Seattle hospital. Nora is one of the characters from Abby's group who was present for Joel's murder, so Ellie seeks her out for information on Abby's whereabouts.

Ellie eventually corners Nora in an area intoxicated by the spores, leading Nora to believe they're both dead, providing some last-minute satisfaction to her imminent doom. That satisfaction is wiped away once Ellie reveals her immunity. Nora connects the dots, realizing that Ellie was the immune girl from Salt Lake City, saying, "You're her." This demonstrates that the remaining Fireflies knew of her existence, but not enough to pursue her like they did with Joel.

1 Maria

Maria Is Told Off-Screen In The Games

Maria is Tommy's wife, and she has a heightened role in the TV series compared to the video games. That said, Tommy and she share a close bond, and it would be impossible for him to keep this secret from her. Though it hasn't been revealed yet in the show, when Dina realizes Ellie's immunity in the game, Ellie explains that only Joel, Tommy, and Maria knew in Jackson. Maria is one of the primary leaders of the Jackson commune, so it speaks to the strength of her love for Tommy that she would keep this secret in The Last of Us.