So here’s the thing: out of all your wizarding students and house elves and headmasters and Death Eaters and muggles and centaurs, there is really only one person who determines the course of the Harry Potter series.

It’s Neville Longbottom.

Neville Longbottom has quite a following in the Harry Potter fandom, and for good reason—he is humble and noble, brave and kind, he’s a wonderful friend and a fierce supporter. Neville is what most Gryffindors would be like in the real world, a person capable of heroic feats under dire circumstances, but not inclined to them every waking moment. Neville understands that it’s not about being loud and brash every day, it’s about picking your battles and knowing what’s dear and worth fighting for.

Neville also might have been the chosen one, according to Trelawney’s prophecy. If Voldemort had simply decided he was the real threat, then Harry could have avoided his mark and lived life out… well, a little more normally.

But it’s not quite so simple as all that. See, Rowling largely operates Harry’s generation in a clear system of parallels to the previous generation, Marauders and all. Harry is his father—Quidditch star, a little pig-headed sometimes, an excellent leader. Ron is Sirius Black—snarky and fun, loyal to a fault, mired in self-doubts. Hermione is Remus Lupin—book smart and meticulous, always level-headed, unfailingly perceptive. Ginny is Lily Evans—a firecracker, clever and kind, unwilling to take excuses. Draco Malfoy is Severus Snape—a natural foil to Harry, pretentious, possessed of the frailest ego and also deeper sense of right and wrong when it counts. And guess what?

Neville Longbottom is Peter Pettigrew.

Think about it—the tag along friend who looks up to the trio, but is looked down on by everyone else for not being remarkably talented or suave. Someone who is trusted with a lot of Harry’s most important secrets, in a perfect position to give everyone away. “Foolish boy,” as McGonagall said of little Pettigrew. Another pureblood who has no respect from the higher-up notable wizarding families. Gullible, the easy mark, someone who other children make fun of when Harry, Hermione, and Ron aren’t on hand to defend him. Neville is Peter’s brand new analog in the story.

Or, at least, he could have been. Neville is a perfect example of how one single ingredient in the recipe can either ruin your casserole (or stew, or treacle tart, whatever you like), or utterly perfect your whole dish. Neville is the tide-turner, the shiny hinge. And all because he happens to be in the same position as Wormtail… but makes all the hard choices that Pettigrew refused the first time around. Other characters are in similar positions, but none of them go so far as Neville. None of them prove that the shaping of destiny is all on the individual the way he does.

Of course, Neville does embody many characteristics that are worth emulating all on his own, but the more important part of that equation is how his strengths fill a gap in group dynamics that the Marauders were missing. Harry and company need Neville in the exact way that James and Lily and the Order of the Phoenix needed Peter. The difference is that Neville is more than up to the task.

It’s a lesson in self-worth under stronger personalities that most human beings could do with at some point or another. Because society at large insists that the only people of value are leaders and their closest confederates, people like Neville are dismissed at first blush much in the same manner that he is dismissed by his classmates in his first years at Hogwarts. But that lack of confidence from his peers doesn’t lead him to throw in the towel; his self-deprecation eventually turns into a dogged insistence on growing his skill set, on offering his help whether or not it’s been called for, on figuring out how he can best be of use in the coming fight.

Peter Pettigrew was in that very same place, but let his weaknesses carry through life; he hero-worshipped James and Sirius, then simply transferred that sensibility to Voldemort. He is the ultimate follower, he moves to what he perceives as the strongest single voice in the room. Which is the reason why Peter doesn’t seem to lose much sleep over his decisions—while he’s aware that what he has done is wrong, his basic excuse for everything is “But You Know Who had so much power! There was no other choice that makes sense!” Sirius says that he would have died rather than betray Lily and James the way Peter did, but the real point to take away is that dying was never the only option. If Peter had worked a little harder, relied less on the protection of others, believed in the power of his friendships and family, he need never have made those choices in the first place.

This is why Neville’s very first act of heroism is a perfect juxtaposition to Peter’s failings when he stands up to Harry, Ron, and Hermione in the Philosopher’s Stone. Dumbledore recognizes it as such, and rewards him for his body bind with the final points needed to win Gryffindor the House Cup. He makes it Neville’s personal victory by announcing him last. (You have to surmise that Dumbledore sees how history might repeat itself and is relieved to see Neville going down a different road.) Where Peter spent his life in the shadow of his friends, remembered even by professors as little more than a sycophant—recall that Professor McGonagall thinks of him primarily as that boy who trailed after James and Sirius—Neville steps away from that position immediately and shows everyone that while he may be meek, he’s no one to mess around with.

More important than Neville’s defense of what’s right is his role as a keeper of hope. Neville comes to Harry’s aid when no one believes what he says, fights alongside him when most flee at the prospect of real danger, then keeps his platoon going from inside Hogwarts during Harry’s absence. He has the hardest job of anyone, and it’s a responsibility he takes on without being asked or expected to do so. He houses refuges in the Room of Requirement, lets everyone know that Dumbledore’s Army is alive and well. Epic tales always demand that someone never give up the cause no matter how bleak things seem, and that’s Neville through and through. His friends are kidnapped, tortured and gone, but he stays at Hogwarts while two Death Eaters are teaching classes and keeps the candle burning for Harry, Ron, and Hermione’s return. If he hadn’t, who knows if the Battle of Hogwarts could have even taken place. Still, Harry didn’t come up with Neville’s role in a brilliant moment of strategic awareness—they simply got lucky that Neville decided he wanted the job.

You could argue that his parentage has a lot to do with his journey. Frank and Alice Longbottom were tortured to insanity by the Lestranges, and so he has a deeply personal reason to stand against Voldemort. But by all accounts, Peter also had a good family who would have been horrified by the choices he made. This ties into Pettigrew’s decision to fake his own death—his mother could believe that he died a hero. Neville’s situation is exactly opposite and once again shows Peter up in every sense; he fights for a family that is no longer present, wants to make his parents proud though they will never consciously know what he is doing in their memory.

In the final hour, Neville is given a chance to make the same cowardly choice that Peter did, to join Voldemort’s forces and go the easy route. And instead he pulls Godric Gryffindor’s sword out of a burning Sorting Hat and destroys the final horcrux by slicing off Nagini’s head. It couldn’t be more clear than it is in that moment; Harry needs Neville in order to end this war just as much as he needs Ron and Hermione, the same way that his parents needed Peter. And it is true that Harry is a much better friend to Neville than his father might have been to Peter, but at the end of the day, that’s still down to Neville—down to a boy who demanded respect from his friends right from the start, no matter how small or unremarkable he felt. Who had the gumption to do what he knew was right, not when it was hard but because it was hard.

That distinction makes Neville Longbottom the truest of Gryffindors and a surprising balancing point of the entire Harry Potter narrative. Who Peter Pettigrew might have been had he understood that courage wasn’t about blind action, but about doing what was needed even if no one ever asked. In a world of leaders and followers, there are some who don’t attempt to fit either mold, and it is those distinct few who really determine the future of us all. That is what Neville Longbottom can teach us.

Emmet Asher-Perrin always loved how Potter generations paralleled so beautifully. You can bug her on Twitter and read more of her work here and elsewhere.