Although it is generally accepted that the massive bridge spanning the space between Lothric and the Undead Settlement was built to connect the two, some have argued that this is not actually the case, as it clearly leads to someplace left of Lothric rather than the city’s main gate. Indeed, while it now leads to nowhere as can be seen from certain angles, the bridge was intended to lead somewhere else during development. Early promotional illustrations of the Dark Souls III (DS3) game world labels it the “Great Bridge of Pilgrims” (巡礼の大橋) and portrays the viaduct as heading to a forested area at the foot of the much higher mountain which Lothric sat upon. We do see pilgrims of Londor on this bridge in the final game, but why would they or anyone else make pilgrimage to this forest and not Lothric, and why would this apparent holy land even be at Lothric?
According to its description, the unused Bridge Key would have opened a gate at a deeper section of the giant bridge, somewhere much further along than where we are dropped off to reach the Undead Settlement. The deepest part we can explore does have a gateway, one of several checkpoints which can be found along the length of the entire causeway. Although this particular gateway is blocked with rubble in-game, the bridge having once included or led to a functional gate for us to unlock is feasible. Requiring a key also fits with the order of events for this earlier version of the game.
Descriptions for cutscene triggers confirm that there would have been a transition from Lothric to the bridge. This is separate from the cutscene transitioning us from Lothric to the end of the bridge where we enter the Undead Settlement, so it must refer to the deeper portion, which we can only enter from Farron Keep in-game. And based on the numbering of these triggers, we would have gone there after heading to the town, defeating the “Lone King” of the “Abandoned Capital” (廃都) which ultimately became the Profaned Capital, and then returning back to Lothric to defeat the Twin Princes. While this doesn’t present a complete roadmap for all the areas and bosses we would encounter, it does indicate that we would have only been expected to go to the bridge after defeating the princes’ roughly halfway through the game. In that case, it makes sense to prevent us from fully exploring it until we acquire this key, which would have presumably been in the boss’ possession — it is certainly something that Lothric royalty would own.
The key’s description suggests that this bridge wasn’t constructed by humans, implying that it would be too massive an undertaking. A project too big for human hands brings to mind Irithyll’s giant slaves, who were implied to be responsible for several massive construction projects in the original Dark Souls. (DS1) If the Boreal Valley was involved in building it, then there must be great religious importance to wherever this bridge leads. According to the description, it hides a sacrament, literally a “secret mark” (秘跡) in reference to divine mysteries. Not only does this reinforce the notion of the gate protecting something holy, it also implies that what lied beyond was hidden from the general public. Even so, it is theorized to be the domain of gods, though the text doesn’t clarify how many or for what purpose. Taken together, everything points to the bridge bringing us to one scrapped area in particular.
Key which opens the closed gate of the bridge interior.
It is said that the interior of the giant bridge which couldn’t possibly have been made by human hands hides a sacrament that no one has seen yet. One theory says that it is the territory of gods there, but…
Shinbo (神墓) is the internal name for a graveyard area which now only exists in the game files, though the assets for many of its headstones were ultimately reused for the royal mausoleum in the The Ringed City DLC. Since this codename describes graves of gods, I will refer to this area as “Divine Graves”. Although the map itself is untextured, we can confirm from remaining assets that it would have been covered in trees and situated roughly just left of Lothric and behind the Undead Settlement. This more or less matches the geography for the location the great bridge headed toward in early promotional material. We can thus be certain that Divine Graves is the “territory of gods” that the pilgrims would have been flocking to; the only question is why. In all likelihood, it would have been the graveyard for the Lords of Cinder.
The entity comprised of the souls of all the past Lords of Cinder is considered to be the gods for what remains of Lordran at the Kiln of the First Flame. Likewise, the opening cinematic portrays the Lords’ burial ground with no distinct landmarks identifiable with the Cemetery of Ash, which the name would imply is exclusive to unkindled. We can thereby only infer that these entombed Kings of Kindling are somewhere within range of Firelink Shrine’s bell toll; given that Greirat apparently heard the bell from his cell at Lothric’s front wall, that is a wide radius. How convenient then that there would have been another graveyard for “gods” located directly in front of the Cemetery of Ash — we can even see Firelink Shrine in the background behind Divine Graves’ location in promotional illustrations from both before and after DS3’s release. These two areas might have been intended to be part of one larger graveyard, perhaps with a shortcut connecting them, but the juxtaposition suggests a connection, regardless.
… Ah, you don’t seem to be a prison guard. More likely an outsider, and moreover, it’s after the sound of that bell… By any chance, are you a fireless ash?
Some have instead posited a connection between Divine Graves and the pygmies. The headstones with holes in their center were ultimately repurposed for the pygmy capital, and the unused variant in particular have roots associated with human dendrofication growing around those holes. There are also pots with similar holes and branches growing out of them. From this, it is theorized that Lothric would have been built upon an old pygmy burial ground, with the ancient men as its gods. Londor’s pilgrimage there would therefore relate to man’s Dark roots. However, even assuming that Lothric’s dramatic transition from Dark worship to firelinking is feasible, the hole imagery doesn’t preclude a Lord of Cinder’s grave — the ritual is mainly performed by bearers of the Darksign, after all. Inheriting the First Flame also doesn’t prevent the Dark’s stagnation as Aldrich exemplifies. And finally, the pilgrims would have a far better reason for heading to the Lords’ graveyard.
Examining the layout of Divine Graves in map data for the low resolution model used on the horizon, the area starts as the forested cemetery only to gradually become a series of ruins and caverns cutting deep into the mountain directly below Lothric. What could possibly be down there that would merit a cemetery just outside of it? More than likely the means to reach the First Flame. Indeed, the in-game process for reaching the Kiln is, admittedly, inefficient even for an emergency system. Surely, Lothric or Irithyll would have created a more straightforward passage to the fire hiding in this land akin to the Firelink Chamber in DS1 or Throne of Want in DS2, both of which were located more or less beneath the castle lording over their game’s respective setting. This passage would also have to be located somewhere convenient for the burial of Lords and unkindled alike, much like Firelink Shrine. These caverns at Divine Graves check all the boxes.
Further supporting this is the presence of Consumed King Oceiros in this area. Though the boss was still only called “Dragon Angel” at this point in development, his character model, animations, and dialogue are identical to his depiction in the final game. In other words, the character seems to have always been the mad king of Lothric who became a dragon and fathered Ocelotte out of a twisted obsession with siring a Lord of Cinder. In that case, his appearance in Divine Graves is no surprise. Much like how he went to the temple ruins leading to Firelink Shrine, the Dragon Angel would have gone to the Lord of Cinder graveyard providing him similar passage to the Kiln of the First Flame. Based on his dialogue, he would have either been squatting there waiting on Ocelotte like in the final game or be somehow prevented from continuing onward, which would also explain why we are required to take an alternate path in our journey.
A graveyard for firelinking gods connected to the Cemetery of Ash, Firelink Shrine, and the Kiln of the First Flame would motivate Irithyll to construct a massive bridge with multiple checkpoints securing who goes in. It would likewise prompt Lothric to send all of its Undead to a settlement at the start of this causeway — definitely more reasonable than dumping all but a select few right at its only entryway. The kingdom overseeing this system would naturally result in its royalty possessing keys to the bridge, especially a prince whose prospective firelinking was imminent. And both countries would want to keep the nature of this place secret from the gods’ enemies. Indeed, considering Yuria’s stated goal in the final game, the pilgrims would have most likely been traveling the great bridge as part of Londor’s plan to subvert the First Flame.
All of this is to say that the bridge clearly wasn’t supposed to lead to Lothric originally. However, it most certainly does now. The Stray Demon patrolling the blocked end of the bridge closest to Lothric is the city’s gatekeeper, indicating that the gate he guards is right there behind him. The path from the city to the Undead Settlement was also broken by the emergence of the “High Wall”, an apparent reference to the mountain elevating the city above the bridge, town, and everything else. Indeed, the bridge and town alike have been torn asunder by some sort of seismic activity — presumably another byproduct of the world’s stagnation — and the viaduct is the only path feasibly connecting it back to the city. Even the promotional artwork for the final game dramatically shortens the mountain the city sits atop while pointing the bridge directly toward its main gate, making the High Wall’s effects look more believable.
There was undoubtedly a conscious a decision to make the bridge the main route to Lothric. But if so, why not reflect this in-game? Probably because FromSoftware didn’t have time or resources to do so. The bridge’s location relative to everything else can be seen from most areas. And considering how easy it is to find incomplete geometry and textures for the surrounding scenery by simply looking below our immediate line of sight, the developers were unlikely to reorient one whole set piece for every area. Artwork and item descriptions cover the intended image, and most players probably weren’t expected to notice the inconsistency in a background detail whilst exploring the world. Seismic activity around Lothric stemming from the drift also seemed to always be the intention, so cutting Divine Graves and any reference to the giant bridge being impossible for humans to build was enough to make players link the city with the path to the town at its foot.