It's been ten years since the release of Demon's Souls, the underrated first installment in the long-running Souls series by FromSoftware. Hidetaka Miyazaki's unsung masterpiece contains many fascinating design decisions, including its emphasis on environmental storytelling, its deliberately slow and methodical combat, and its shortcut-laden level design. Perhaps one of its most influential aspects, though, is its approach to online multiplayer. Demon's Souls facilitates interactions between its players in innovative ways, and there's more going on under the hood when it comes to how players influence each other's worlds. Unfortunately, the servers for Demon's Souls were shut down back in February 2018, so you won't be able to play the game online anymore. With that in mind, now seems like the perfect time to descend into the Deep Fog once more and take a look at how the online aspects of Demon's Souls worked.

Demon's Souls director Hidetaka Miyazaki's inspiration for the game's multiplayer is intriguing in itself. Miyazaki was driving after a heavy snowfall when a car in front of him suddenly stopped and began to slip. This caused a chain reaction in which cars behind Miyazaki abruptly stopped, hitting the car in front and allowing all of the cars stuck in the jam to move. Each car took turns nudging the one in front so that the jam could be resolved. Miyazaki says that on the way home, he wondered about whether he would have been friends with the people who had helped him if they'd met face-to-face and realized that a game could have multiplayer interactions between people who never needed to talk or even know each other in real life. Thus was the multiplayer in Demon's Souls born, thanks to a philosophy Miyazaki calls "mutual assistance between transient people." That same philosophy also birthed the competitive elements of Demon's Souls' multiplayer; after all, if players can quietly help each other, then they must surely be able to quietly harm each other too.

The blue phantoms of Demon's Souls could be your worst enemies in real life and you'd never know.

If you're familiar with Dark Souls, you probably have a rough idea of how the multiplayer gameplay in Demon's Souls operated. Players could use a special item to leave summon signs behind, allowing them to be summoned into other players' worlds for co-op. Up to two players could be summoned into each player's world for a single one of Demon's Souls' levels, and signs could only be left in levels where the boss had not yet been defeated. Each player involved in the boss fight received rewards for participating, and Blue Phantoms (player characters) who weren't in human form had their bodies restored by winning. Players couldn't make progress in their own worlds by killing bosses as a Blue Phantom, so you could only progress through the game through co-op by being the host yourself. Much like Dark Souls, Demon's Souls made it very difficult for players to directly communicate with one another, restricting player-to-player communication to a fairly basic emote system. In this way, Miyazaki made sure animosity between co-op players was almost impossible and reinforced the lonely camaraderie of Demon's Souls' world.

On the other side of the coin, there was player versus player combat. Unlike co-op, players didn't necessarily choose to engage in combat with invaders. If you wanted to invade another player's world in Demon's Souls, you would need to use an item called the Black Eye Stone. If playing online, this item could be obtained by defeating any player who invaded you, and if offline then the first NPC phantom defeated would drop it. The Black Eye Stone sent the player to another adventurer's world to battle them in honorable (or dishonorable, as was often the case) combat. If the invader successfully defeated the host player, they would be restored to human form in their own world. If the host defeated the invader, they would receive souls as a reward, and the invader would gain (and lose) nothing. Interestingly, if the invader died by falling or succumbing to one of the game's many deadly traps, they would lose a Soul Level, weakening them slightly. Demon's Souls remains the only Souls title to punish players by permanently removing levels from them, both as an invader and when facing a late-game boss we won't spoil.

Don't fall afoul of the game's player and non-player Black Phantoms.

Of course, if you were of a bloodthirsty disposition, Demon's Souls also offered you the ability to actively invite invaders to your world for one-on-one combat. Doing so required an item called the Red Eye Stone, which could only be obtained in one of the game's two endings. Using the Red Eye Stone placed a red summoning symbol on the ground in other players' worlds, which they could then use to summon you for the specific purpose of fighting you. Demon's Souls allowed players to define how much interaction they wanted to have with others to a certain extent, but it asked its players to accept everything about their fellow humans if they wanted to open themselves up to communication. If you wanted to summon helpful Blue Phantoms into your world, you also needed to accept the risk that Black Phantoms could show up and potentially ruin everyone's day. By accepting help, you also opened yourself up to betrayal.

The multiplayer invasion aspect of Demon's Souls featured heavily in one of its mid-game bosses. The Old Monk, a corrupt official residing in the Tower of Latria, would periodically summon other players to fight for him as part of the boss encounter. Anyone who uses one of the game's multiplayer items—a Blue, Red, or Black Eye Stone—anywhere in the Tower of Latria could potentially be summoned into the Old Monk's boss arena as part of the encounter. If no invading players were available, the Old Monk would instead default to using an NPC to fight the player. The encounter is of course still plenty challenging offline, but adding the danger and unpredictability of another player during one of the game's until-then entirely PvE bosses was a unique stroke. Dark Souls 2 and Dark Souls 3 would both revisit this idea—the Looking Glass Knight in the former, and the Spear of the Church in the latter's Ringed City DLC—thus demonstrating the lasting appeal of using an enemy player as a boss encounter.

A player is summoned by the Old Monk boss to do battle.

One of the most interesting aspects of Demon's Souls' approach to multiplayer was its Tendency systems. You can think of Tendency as roughly analogous to karma or alignment systems in other games; like karma, Tendency changes depending on your actions in the world, and there are two extremes available based on the nature of the player's deeds. Tendency remains a thoroughly unique notion among video games, with no direct precedent and arguably no real successor. FromSoftware quickly ditched Tendency in Dark Souls, replacing it with the Covenant system. Covenants don't quite work the same as Tendency did, but the systems are similar in the ways they attempt to encourage PvP combat and ambient multiplayer. Still, with the loss of Tendency, something special was arguably lost from the games' formula. The Tendency system is a little tricky to get one's head around at first glance, but it's an intricate and well-realized mechanic that admirably demonstrates Miyazaki's "mutual assistance" philosophy.

There are two kinds of Tendency. The first is Character Tendency, a stat which only affects the player's character. The actions the player took during the game affected their Tendency in positive or negative ways, which caused the difficulty of the game to increase or decrease accordingly. For example, killing Black Phantom invaders would shift the player's Tendency towards White, while killing friendly NPCs or invading other players' worlds as a Black Phantom would move the player closer to Black Tendency. Just as with traditional karma systems, there was a reward for "goodness" (or Pure White Tendency) in the form of increased attack power in Soul Form, as well as increased attack damage when engaging in co-op with another host player as a Blue Phantom. Black Tendency was "punished" with reduced maximum Soul Form HP, but there were benefits to having Pure Black Character Tendency too, including extra quests from a unique NPC and increased power as an invading Black Phantom.

Secondly, there was World Tendency, which was server-wide. Every single player who played online in Demon's Souls contributed to the World Tendency of that server, so the actions of each player were calculated and weighed against the actions of others. World Tendency operated in a similar way to Character Tendency, but the Tendency of each world is the same for all of its players regardless of how they contributed towards that Tendency. For example, let's say you set out to play a virtuous knight. You kill no friendly NPCs, you help other players as a Blue Phantom and you dispatch Red Phantoms wherever you find them. Your Character Tendency would be close to Pure White, but if you found yourself on a server full of players who favored Black Tendency actions, you'd end up with a Pure Black World Tendency, which would make the game more difficult for you while increasing the rewards you obtained for successfully killing enemies.

Don't kill friendly NPCs if you want White World Tendency.

In this way, Miyazaki showed players how a world can be shaped by everyone in it and how the consequences of each person's actions can affect others. Pure White World Tendency would make enemies weaker but also reduce the rewards players would receive for killing them. Pure Black World Tendency made enemies harder by giving them extra HP, as well as increased attack power and defense, but consequently gave players more souls for kills. When a world's Tendency was Pure Black, there would also be unique Black Phantoms present throughout each of the game's five different areas that could be killed for items. There was even an enemy in Demon's Souls that only appeared when a world's Tendency was close to Pure Black: the Primeval Demon, which dropped the Colorless Demon's Soul item required for upgrades and specific Miracle spells in the game. Thus, it was not entirely a bad thing for a world's Tendency to be Pure Black; although the game's difficulty did significantly increase, this was compensated for by extra items and enemies that couldn't be encountered in the game otherwise.

Just like Character Tendency, specific actions would shift the World Tendency towards white or black. Killing demon bosses, as well as the game's twin Red and Blue Dragons, would shift one towards White Tendency, as would killing Pure Black World Tendency NPC Phantoms like Executioner Miralda or Scirvir the Wanderer (these phantoms also had human forms, and killing those would shift the world towards Pure Black Tendency). Killing invading Black Phantoms would also shift World Tendency towards White. Black Tendency actions include dying outside the Nexus, killing a certain "boss" later in the game, and other such actions. This system is slightly reminiscent of MMOs, in which a shared world can be altered by players killing certain crucial NPCs or bosses that are required for quests.

Miyazaki and FromSoftware released Dark Souls, the spiritual successor to Demon's Souls, in 2011. That game's PvP and multiplayer revolved around the new Humanity item and stat, as well as Covenants, factions continually battling in certain areas which players could join in order to assist or hinder each other. Like World Tendency, Covenants could still affect players even if they themselves never joined one, with certain areas being "controlled" by covenants and protected by members. If, for example, the player is wandering through the Darkroot Garden area, they may be invaded by members of the Forest Hunter covenant even if they themselves have never interacted with the Covenant system. Dark Souls' world multiplayer is a little less oblique, and each successive installment attempts to iterate on and explain the Covenant formula a little better, but Covenants don't have the ability to shift the entire world one way or another for all players on a server.

Oswald of Carim is the go-to NPC in Dark Souls for players who have "sinned."

Similarly, in Dark Souls, the concept of a "Sin" was introduced, which is not dissimilar to Black World Tendency. In PvE, sins apply to players attacking NPCs or performing certain actions of which NPCs disapprove, and can be absolved through the use of Oswald, an NPC who sits atop the Bell Gargoyles' tower once the boss has been defeated. PvP sins operate a little differently. If a player is invaded and killed, they can "indict" the player who killed them through the use of an item. Once a player is "indicted," they open themselves up to be invaded by members of the Blades of the Darkmoon covenant in retribution. Again, this system is only nominally similar to the Tendency system in that the entire server doesn't become affected; only the players interacting with one another have their worlds or characters changed as a result of the multiplayer interaction.

Tendency is a unique and intriguing system that does have successors in the form of the Souls games' approach to multiplayer, but the series would never again try something quite so large-scale. The mixture of ambient world alteration, active multiplayer elements, and persistent difficulty shifts is utterly unique to Demon's Souls, like many things about that game, and until FromSoftware takes another foray into this system, we're not likely to see it repeated anywhere else. Tendency may have been a bit confusing to start with, but it was just one of many interesting, intricate, and idiosyncratic strings to Demon's Souls' bow.