The key to Succession has been staring you in the face for four seasons and has been played off as comic relief. It is the neglected son Connor Roy, played impeccably by Alan Ruck.

Connor is often ignored by the rest of the family. His half-siblings and father seem to view him as irretrievably goofy. But the main theme of Succession is highlighted by his character: he is the oldest son, and he is irrelevant. He even has to remind his half-siblings that he — not Kendall — is the oldest son in the season 3 finale.

Still, Connor’s not in the race to replace his father, Logan Roy. He’s not even tasked with anything important. His mother got shipped off to “the funny farm,” and Logan remarried. In the first season, when the siblings gather at the boathouse before Shiv’s wedding, he isn’t invited. In the most recent episode — his wedding — his father skips the celebration, only to die on an airplane. His half-siblings don’t think to get him to say goodbye to his father until after Logan is already most likely dead.

They don’t think of him at all for 15 minutes. At his wedding.

When Connor does get the news, Ruck’s portrayal is heart-wrenching. He is in the middle of having a meltdown about his wedding cake because it is made of the same kind of sponge cake he ate for a week after his mother was institutionalized. In the first season’s “Sad Sack Wasp Trap,” Connor freaks out about the butter being wrong during the charity gala for the Roy Endowment Creative New York. The call back to Connor’s micromanaging an event suggests something about his past, something horrible. He learned that management style from someone, and it wasn’t Logan.

When Shiv and Kendall get Connor to forget about the cake for a few minutes, Shiv says, “They think he’s dead.” And Connor stares straight at her, seemingly unemotional: “Well, is he?”

Kendall says they don’t know, but Logan is undergoing heart compressions. “Oh man,” Connor says. “He never even liked me.”

Then he immediately begins to comfort his distraught younger siblings, swallowing his own feelings. “You know what, I’m sorry,” he says to Kendall. “He did. He did.”

Of all the children, Connor seems to be the one who’s most aware that remaining in his father’s orbit is a trap. But Connor is also what all the rest of the Roys fear becoming. He is a warning sign to his younger half-siblings: if they step out of Logan’s orbit, they’ll be just as irrelevant and unloved. After all, if Connor hadn’t been cast aside, they wouldn’t be competing for Logan’s attention at all.

In the first season, Connor’s New Mexico ranch, Austerlitz, is the setting for an attempt at family therapy. The attempt is more PR stunt than actual healing, much to Connor’s disappointment because, unlike his siblings and his father, he does want an actual family. The family business, which has Shiv, Kendall, and Roman attempting to tear each other apart in order to succeed their father, has warped the relationships beyond repair.

Previous seasons have focused on the other siblings. The first season is primarily about Kendall. The second, Shiv. The third, Roman. Arguably, Connor is due — and his rehearsal dinner and wedding provide the backdrop for two of the most dramatic episodes of the show so far.

Earlier this season, Connor’s siblings skip his rehearsal dinner to plot against their father. They catch bride-to-be Willa running out and make a belated attempt to console Connor by taking him out to karaoke. And though Connor, after singing Leonard Cohen’s “Famous Blue Raincoat,” says his superpower is not needing love — “The good thing about having a family that doesn’t love you is that you learn to live without it” — he also took his younger siblings fly-fishing when Logan wouldn’t go. Maybe Connor tells himself he doesn’t need love because he doesn’t believe he’ll ever get it.

Certainly the sibling-bonding karaoke moment is immediately upstaged by the arrival of Logan.

Throughout Succession, Ruck’s portrayal of the cast-aside eldest has been phenomenal. Sure, Connor is mostly there for punchlines — his presidential campaign provides most of them — but even through the jokes, Ruck manages to convey pathos. The switch from his honest reaction to Logan’s death to comforting his younger siblings tells you precisely who Connor is: more absurd than the other three but also more human. Kinder.

It took a brilliant actor to pull that off. I’d like to see what else Ruck can do.