There are a lot of significant siblings in the Game of Thrones universe, like the Starks, the Lannisters, and the Tyrells. Their relationships might be varying levels of dysfunctional -- looking at you, Jaime and Cersei -- but no matter what, they have each other’s backs amidst the chaos of battles and ever-changing alliances.

Two notable exceptions to that rule? Sandor and Gregor Clegane, otherwise known as the Hound and the Mountain.

The two have hated each other since older brother Gregor shoved young Sandor’s face into a fire when they were kids. In adulthood, Gregor was named a Ser despite his reputation as a rapist and murderer. Sandor, meanwhile, became Joffrey’s personal bodyguard. (He’d also be forever cynical of lords and ladies after his brother became Ser Clegane.)

Seven seasons into the show, both brothers are still alive (kind of) and important to the story in different ways. The Hound is traveling with the Brotherhood Without Banners, while the Mountain has become Cersei’s hired muscle. They might be side characters now, but there are rumors that they’re an important part of the series’ ending. Before we finish up season seven, here are 16 Things You Didn’t Know About The Hound And The Mountain.

Fans believe there will be a final “Cleganebowl” showdown

A Mountain vs. Hound fight was teased way back in season one, when the Hound stops his older brother from cleaving Loras Tyrell in half. However, that’s nothing compared to the epic battle that fans are convinced will happen towards the end of the series. Picture a climactic battle between two of the best and biggest fighters in Westeros, with the added rage of a lifetime of resentment, and you have Cleganebowl.

Originally, fans theorized that the Clegane brothers would be forced to fight when The Mountain was named as Cersei’s champion in a trial by combat. Tommen outlawed trial by combat last season, but the theory hasn’t died. Scenes from the season seven trailer the season 7 finale, there's a very real chance that the Cleganebowl we've all been waiting for is right around the corner.

The Hound’s horse is named after a god

Before this season, when the Hound seems to become a follower of the Lord of Light, it was hard to picture Sandor Clegane as a religious man. (He’s even been known to curse the gods on several occasions.) It might surprise fans to learn that his black warhorse is actually named after one of the Seven, the gods who influence most of southern Westeros.

In typical fashion, the horse is named Stranger, after the seventh and most mysterious god in the Faith of the Seven. The Stranger is the god of death and the unknown. People also rarely pray to it. For a man who enjoys killing as much as the Hound, it’s fitting that he would name the horse he rides into battle after the god of death.

The Mountain has his own soldiers

Gregor Clegane probably has the power and strength of an entire army in his little finger. However, if you want to be even more terrified of the humongous man, consider the fact that he has his own soldiers, called the Mountain’s Men. Imagine going up against both the Mountain and his sworn swords.

We’ve seen a few of them pop up over the course of the show, though you might not have made the connection. The Tickler (killed by Arya), was one of the Mountain’s Men, as was Polliver -- though he was in service to both the Mountain and Ser Amory Lorch on the show. All of the men, like Gregor himself, are known for their extreme violence and cruelty.

The Mountain’s Men have obviously disbanded since their leader is “dead,” but they wreaked some serious havoc on the countryside before that.

The Hound killed his first man as a child

Sandor Clegane has said multiple times that not only is he good at killing, he enjoys it. He might not be as deranged as his brother, but he still seeks out jobs that will let him kill ‘legally’. He’s clear that he doesn’t think much of the distinction, though -- killing is killing, whether you have a fancy title or not.

It turns out that the Hound has been a killing machine probably since he hit puberty. He says in A Game of Thrones that he killed his first man when he was just twelve years old. Given his age and the time period, we can guess that this was probably during (or around the time of) Robert’s Rebellion. It wasn’t just the Stark and Baratheon boys who got their first taste of war back then.

The Mountain has been portrayed by 3 actors

We’ve seen so many different faces and characters of the course of Game of Thrones that it can be hard to keep people straight. If you didn’t notice that the Mountain has been played by three different people, we can hardly blame you. There’s a lot going on.

In season 1, the Mountain was played by professional wrestler Conan Stevens. However, he left the show after the first season to play the Orc king in The Hobbit prequel trilogy. He was replaced by Ian Whyte for the second season, who also played the White Walker in the pilot. Whyte moved on to play wildling giants (including Wun-Wun!), so the Mountain has been portrayed by Hafþór Júlíus Björnsson since then.

Björnsson is 6’9” and 400 pounds, so we think they ended up with the perfect actor.

The Hound’s face is more terrifying in the books

We’re all familiar with the slightly melted half of the Hound’s face on the show. In typical show-biz fashion, he’s just disfigured enough for it to be distinctive, but not too badly to be truly disturbing. (The same goes for Tyrion, who’s technically supposed to be missing a nose.)

In the books, the wounds left by his sadistic older brother are far more disturbing. The right side of his face is completely burned, and his ear is just a stump on the side of his head. The burned side is black, with a few oozing red craters. There’s a mass of scar tissue around his eye, and a bit of bone showing on his jaw.

This would be impossible to pull off on multiple episodes of a TV show for a number of reasons...but it would still be cool as hell.

The Mountain is 8 feet tall and 420 pounds

It’s hard not to think that Björnsson was just meant to play the role of the Mountain. Besides his strength and undefeated reputation in battle, Gregor Clegane is known for being an absolutely humongous man. His nickname isn’t “The Mountain That Rides” for nothing, folks.

His character is meant to be eight feet tall and 420 pounds of sheer muscle. He has to have custom armor made for him given his size, and it’s the heaviest in all of Westeros. He’s also so strong that he’s able to wield a six-foot-long sword in battle with just one hand. Rumor has it he’s cut men completely in half before.

Given the height and weight mentioned above of Mountain actor Björnsson, we’d say that’s pretty perfect casting - even if he's just a touch smaller than the monstrosity of the source material.

Sansa formed an odd bond with The Hound

Sansa Stark and the Hound didn’t exactly get off to the best start -- after all, it the Hound was among the Lannister guards that killed Ned Stark’s bodyguards and arrested him. He’s also present when Joffrey takes Sansa to see her father’s severed head, though Sandor is the only one present who seems to care about her pain.

After Joffrey triggers a city-wide riot in season two, however, it’s the Hound who goes back into the fray to save Sansa from a gang of would-be rapists. And when the Battle of the Blackwater seems bleak, he goes up to her room to offer to take her back to Winterfell and away from the Lannisters. But she refuses out of fear, and the Hound eventually ends up traveling with her younger sister Arya instead.

The Mountain suffered from extreme headaches

So much time is spent on the Mountain’s physical prowess that it’s hard to think of him with any kind of physical weakness at all. In the books, we learn that his body does have one flaw -- he suffers from extreme headaches.

His squire spills the beans that Gregor Clegane chugs milk of the poppy to try to keep the pain at bay. No one knows what caused them. While it could have been an unfortunate side effect of his size, while others think that he got one too many head injuries in battle.

Either way, as the story progressed, the state of Gregor’s head doesn’t matter quite as much as it did in early books...for several reasons, which we’ll get to below.

Sandor almost always wears his hound helm

We see the Hound’s infamous helm in the pilot of the series -- a great identifier for the character and a good way to one of the many people we were introduced to. However, for several reasons, he doesn’t wear it all that often on the show. It’s easy to guess why. A helm like that blocks our view of the actor’s face, it’s a pain to work with, the list goes on.

However, in the books, the hound helm is one of his identifying features. It’s even an important plot point. When no one is sure whether the Hound is alive or dead, reports of a man wearing a hound helm lead people to think he’s alive. Brienne goes in search of him, but it turns out that the raiding man wearing the helm isn’t the Hound at all -- just someone who happened to pick it up.