While the trailers leading up to Succession Season 4, episode 9 teased us with Roman's (Kieran Culkin) eulogy for his father Logan (Brian Cox), the real bombshell comes when Logan's brother Ewan (James Cromwell) takes the stage for a surprise funeral tribute.

Ewan and Logan famously differed on their ideologies, to the point that Ewan spends much of his eulogy lambasting Logan's conservative legacy. "He has wrought the most terrible things," he says, not long after professing his love for his late brother.

SEE ALSO: 'Succession' Season 4: How does episode 9 set up the show's grand finale?

However, before Ewan dives into the public view of Logan Roy, media mogul and industry titan, he speaks on Logan Roy, the child. He tells a "sob story" — his words — about his and Logan's terrifying childhood crossing from Scotland to Canada during World War II. In this moment, Logan isn't the king of the Waystar boardroom, but a frightened child in the hold of a ship. That portrait of Logan's fraught youth continues with Ewan's next vignette, which finally clarifies one of Logan's and Succession's biggest mysteries: What happened to Logan's sister Rose?

What happened to Logan and Ewan's sister Rose in Succession?

James Cromwell and Brian Cox in "Succession." Credit: Peter Kramer / HBO

For all its double crossings, Succession is not a show that tends to keep secrets. The series trusts that its audience can connect dots based on context clues and well-placed dialogue. In turn, we can trust that we'll get the information we need, when we need it. However, in some cases, Succession likes to leave us just a tad in the dark. Rose is one of those cases.

We first learn about Rose in Season 2, episode 8, when the Roy family travels to Dundee, Scotland, to celebrate 50 years of Waystar. There, the Roy siblings attempt to sabotage potential CEO Rhea (Holly Hunter), telling her to bring up Logan's late sister Rose in a toast. It's the first we hear of Rose in the show, and based on Logan's cold reaction to her mention, he'd rather we not hear of her at all.

Later that same episode, Ewan attempts to soothe Logan, saying: "All those years, blaming yourself for Rose... That really wasn't your fault." For Succession, all that matters is that we know Rose exists, and that Logan blames himself for her death. The smaller details of what happened are less important in the moment, but that hasn't stopped audiences from theorizing: Did she die by suicide? Was she lobotomized? As it turns out, the truth is much murkier.

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Ewan reveals that when Logan's aunt and uncle sent him away to a "better school," Logan hated it. "He wasn't well. He was sick. And he mewed and he cried, and in the end he got out and came home, under his own steam," Ewan says. But upon Logan's return home, their baby sister Rose got sick, then passed away.

"He always believed that he brought home the polio, which took her," Ewan continues. "I don't even know if that's true. But our aunt and uncle certainly did nothing to disabuse him of that notion. They let it lie with him."

It's just a few sentences, but it reveals so much: How Rose died, why Logan blames himself, and how the incident furthered his uncle and aunt's emotional abuse — something that Succession had already implied in Season 1, along with physical abuse. However, the mention of Rose is also a reminder of the finality of Logan's death, and of Season 4 itself.

The reveal of Rose's death reminds us Succession is almost at an end.

Brian Cox in "Succession." Credit: Peter Kramer / HBO

Between Logan's death, a tumultuous election, and the looming possibility of a Waystar-GoJo merger, it's clear that Succession's fourth season is the conclusion of the Roys' saga. But nowhere in the season has this sense of an ending sunk in more for me than during the Rose section of Ewan's eulogy.

Since Season 2, Rose's presence has hung over the show, if even only in the farthest background or in written notes. (She appears in Logan's last wishes, as he writes he wishes to be buried with a photo of her.) Whatever guilt Logan feels toward her frames his other familial relationships in a new light: Is he so distant from his own children in part because he can't bear a similar kind of guilt?

Given that Logan is an expert at holding the past at arm's length, we know there's no way he'd ever voluntarily reveal what had happened to Rose. That was something he would take to the grave. I'd long made my peace with not knowing the full extent of the truth as, again, Succession tells us what we need to know. However, Ewan blows all that up in his eulogy, obliterating Logan's own ideas that the past "is all made up," as Logan tells Shiv (Sarah Snook) in Dundee.

We've always known Logan to be the master of his own narrative, so seeing someone tell such an intimate part of his story is shocking. There's no doubt that he would have hated this section of Ewan's eulogy: The reveal of his most personal secret, the public nature of that reveal, and of course, the fact that he simply has no control over who now knows the truth. Yes, Logan has been dead since episode 3, but Ewan's eulogy is one of those moments where you feel both his presence and his absence.

Beyond the dead Logan of it all, Ewan's mention of Rose is also the closest Succession has ever gotten to a shocking backstory drop. It's the kind of secret reveal and resolution you'd only expect from the final episodes of a show, only Succession delivers it not with bombast and hype, but with the quiet sorrow of a conflicted eulogy. Even though she's never been physically present in the show, Rose becomes a harbinger for the end of Succession — and another complicated layer to Logan's mammoth legacy.

The series finale of Succession airs May 28 at 9 p.m. ET on HBO and HBO Max.