Over time, it became clear how much Michonne trusted and needed Carl as well. When they were separated from the group in Season 4’s “Claimed,” Carl was distraught because he thought Judith was dead—which prompted Michonne to share, for the first time, her own story of grief. In the end, that cathartic moment was what prompted Rick to call Michonne Carl’s best friend—a line Carl echoed in Sunday’s midseason premiere. As Michonne answered Carl, “You’re mine, too.”

But perhaps the most crucial moment in Carl and Michonne’s friendship came later—when Carl felt himself consumed by darkness, positive he had become a monster beyond redemption. This was precisely one season after Carl shot a kid in the woods who had already surrendered—a moment Carl recalled on his death bed, saying “it was so easy” to kill that boy. When Carl revealed his morbid thoughts about himself and the world around him to Michonne in Season 4, she refused to let him give up. “I was gone for a long time,” she said, referring to her own extended period of callous grief. Carl and his family, she added, are the ones who brought her back.

In his final moments, Carl also reminded Rick of when he stopped fighting with the other group back at the prison, instead banding together. “We were enemies,” he recalled. “You put away your gun. You did it. So I could change. So I could be who I am now.” The other person who helped Carl become the person he is was Michonne, who responded to Carl’s grief and self-doubt in Season 4 by providing the optimistic path he sorely needed, someone who insists on reaching out and helping a stranger—a selfless move that, in the end, still got him bitten.

As viewers found out Sunday night, that rosy vision of the future we’ve been watching was actually Carl’s all along. He’s the one who sees the true potential for hope in the apocalypse—the one who appears to have gotten through to Rick, who has now vowed to make it happen. As Rick said in the season premiere—in a moment we now know was a flash-forward—“My mercy prevails over my wrath.” Had it not been for Michonne inspiring Carl, none of that would have been possible.

And then there’s one last moment between Carl and Michonne that had a much narrower impact. In Season 6, Michonne scolded Carl for leading a zombified Deanna to her son Spencer, despite the obvious risk to his own life. To Carl, Deanna deserved the mercy of being put down by someone she loved—just like he did for his own mother back in Season 3, when he was just a child. “I’d do it for you,” Carl told Michonne. By then, to Carl, Michonne was like his second mother. But as he lay dying in the midseason premiere, Carl chose a different path: he insisted on taking his own life. “I don’t want you to be sad after this,” he told her. “Or angry. You’re going to have to be strong for my dad. For Judith. For yourself . . . Don’t carry this. Not this part.”

When Carl reached for the gun to shoot himself, Michonne tried to stop him, saying, “It should be—”

“I know. I know,” Carl replied. “Somebody you love. But you can’t do it yourself if I still can. I grew up. I have to do this. Me.”

His final words to Michonne? “I love you.”

In the end, Carl forced both Rick and Michonne to step outside the burning Alexandria church once they had said their goodbyes. As the two sat outside, they could hear the gunshot. Even with his last breath, Carl chose self-sacrifice. Thanks to Michonne, he came back from the brink, and might have just become the one who saved everyone—not just in the short term by waiting out the Saviors’ bombing in the sewers, but in the long term, with a vision for a world without war.