You can play the game offline. The game uses your account PSN login. If you are not logged into the Playstation Network when you launch the game, it will ask if you want to login. Cancel the login to start the game in offline mode. If you are already logged in, you can use the XMB interface to logout by going to the Account Management menu with the Triangle button. For more information on signing in or out, please see the PS3 online manual.
The information on this page assumes you are playing online. If you choose to play offline instead, you will not be able to create or view messages. Also, you will not be able to use the blue, black, or red eye stones to interact with other players.
Regions and Interoperability
There is no region locking for online play based on the region your account or the console are in. However, the three versions, the Asian, the Atlus North American and the Namco Bandai European release of the game use different servers. You can only connect for online play with individuals using the same version of the game as you.
Demon's Souls offers a unique massively multiplayer environment. Players can leave short, pre-programmed messages for other players to view. These messages can be recommended by other players. As an incentive to leave helpful messages, you will be healed if one of your messages gets recommended. Also, messages with high ratings stay present on the ground much longer than unrated messages. If you feel like you could make a useful contribution, put it down on the ground. You never know when a boost of healing may come in handy.
Messages are composed using a template of possible comments, so it is not possible to create original sentences and words. For example, a template may consist of a nearly complete sentence with a missing phrase: "Be wary of _ _ _ ahead." The author can then select from a large list of possible words to insert into this missing phrase in order to create hints or comments that other players can see. Authors can also write single words from the preset lists. Players can leave 3 messages between each fog gate in a world, writing any more will remove the first message created in that area.
To access the message menu, press Select. The authors own messages on the ground are seen as Green. All other messages are a dull Red.
During your travels through Boletaria, you will happen across Bloodstains left by some unfortunate adventurer. Touching the Bloodstain will create a faint red outline of said adventurer, allowing you to see his/her last moments before meeting some painful end or other. If it is your first time through a particular area, pay close attention to these Bloodstains as they will alert you to traps, pitfalls or enemies waiting in ambush.
Note that there is no voice chat in Demon's Souls. Instead you communicate in-game through messages as above, or with emotes. If you hold the select button ('X' in North American and Asian, 'O' for others) for a short time it will display a menu in which the emote can be selected with the d-pad or through the slightly awkward six-axis control system. When using the six-axis method of emoting, a short press of the select button ('X' or 'O') in combination with the appropriate movement is all that is needed.
Bridging Between Worlds
The ghostly white figures you sometimes see moving through the world are an indication of other players in parallel worlds adventuring in the same location as you. You can bridge across to these parallel worlds to join another soul, for good or ill, using different colored Eye Stones.
The servers do enforce level restrictions, so a host cannot summon co-op helpers or be invaded by enemy PvP players who are not close to the same level. However, if you are invading then the other player is considered the host, which means they would be higher level than the reverse.
The level restrictions are always based on the host, who is the person not in soul form. If you are within their range, they can summon you, or you can invade them. So, while a high level character might be able to summon you, the reverse might not be true.
An example of this is a 144 player can summon a 119, but a 119 player cannot summon anyone greater than 140. The exact formula is : Host Soul level +/- (Host Soul Level * .1) + 10. You then take that result and always round the answer down. You can use the Level Range tool to calculate this information.
Blue Eye Stone
In Demon's Souls, a host player can team up with two1 other players online to form a group of adventurers for a single level. The host, who must be alive (in physical body form), will see a bright Blue Soul Sign (a message marker left by another player in soul form, using Blue Eye Stone). The host can view how many times that player was online, and their ranking. The host can then choose to summon that player, who will arrive in soul form as a Blue Phantom.
The host and Blue Phantoms all receive souls for their hard work, and can team up to take out bosses even faster and safer. While you can place a Blue Soul Sign anywhere in the world, the host may only summon blue phantoms for co-op in levels that have not yet been rid of their Boss Demon. After beating a boss, all surviving Blue Phantoms will regain their physical bodies, and go back to their own worlds, but they will not progress in their own games. For example, you will not get a trophy for helping a host player beat the boss. You have to beat it in your own game.
Although there is the option of summoning 1 or 2 Blue Phantoms, there's also the Soul Level range factor, which restricts certain co-op with other players. You must be within the level range of the summoning player. See Level Restrictions above.
Whether you complete the boss fight or die in the other players world you will always be transferred back to your world. If you died from anything other than a Black Phantom, you will be returned to your world with all the souls collected and your health and MP full. If you died to a Black Phantom, you will lose half of your souls. As the co-op session ends, each player is permitted to rate the other player(s) on a grade system which stays with the character, so that in the future, other players can know how good (or bad) a certain player is. From best to worst, the ratings are "S", "A", "B", "C", "D", and "E."
Because the co-op system is not based on your friends list or explicit in-game matchmaking, it can be hard to coordinate co-op with specific players. If you are trying to co-op with an individual, it can be done, but be attentive to the rules, especially the level restrictions and the ability for the host to summon only in levels with the boss not yet defeated. It can help if the Blue Phantom puts their Blue Eye Stone in an uncommon place. It can be annoying to get summoned to a random host if you were trying to meet someone specific. If you want to find someone to play with, here are some PSN IDs you can contact to try and arrange co-op.
Player vs. Player (PvP)
Black Eye Stone
The Black Eye Stone has a slightly different function. It allows a Soul Form player to force their way into another Body Form adventurer's game to hunt down and kill them. Successfully killing the host revives the Black Phantom into his/her body. Regular enemies in the stage do not react to the Black Phantom, even if attacked. Enemies killed by the Black Phantom will only grant Souls to the host. A similar formula applies to using the Black Phantom, although you will never be invaded by another player higher than your soul level.
If the invading Phantom dies due to the environment (e.g. falling off a cliff, rolling ball trap in 1-x, Red Dragon in 1-2, etc) their Soul Level will decrease by one. Further, dying from either poison or plague will also cause the Black Phantom to lose a Soul Level.
Only one Black Phantom can invade a single host at a given time.2
One important thing to remember is that if an invasion is successful and the host and any Blue Phantoms are killed or die, the invader will revive, getting body form back, but will not get any souls from the host's death. The invader will get souls from killing Blue Phantoms.
Red Eye Stone
The Red Eye Stone is obtained by killing the Maiden in Black during the End Game sequence. Red Eye Stones are used to create Red Soul Signs which can be seen by other Body form players of the appropriate Soul Level range. The Body form player, or host, can choose to summon the user of the Red Eye Stone, who will enter the host's world as a Black Phantom. Unlike the Black Eye Stone, the host or any supporting Blue Phantoms will lose a single Soul Level if killed by the Black Phantom, and vice versa.
The difference between an invading Black Phantom from one that was voluntarily summoned by the host is that the Red Eye Stone Phantom enters the world without the "<Insert PSN ID> has invaded" warning.
Trading with other players is possible in Demon's Souls. In order to set up a trade, one player needs to be in human form, and the other in soul form. Like any co-op game, the human-form player would invite the soul form player into their game. While in a game together, players may drop and pick up items as they like. There is no 'Trade-window'. Trading needs to occur under the honor system, i.e. don't trade with someone you don't trust. Note that Blue and Black Phantoms cannot directly interact with items/loot or NPCs, only the host player can, so unless the items are dropped by a player, they cannot be taken by Phantoms.
Keep in mind that Demon Souls obtained from bosses cannot be picked up by Phantoms, including Colorless Demon's Soul.
NPCs and Phantoms
When entering a world as a Blue or Black Phantom, named NPCs in Body Form such as Old King Doran and Blacksmith Ed will appear as a faint white ghost. Phantoms cannot interact or harm these NPCs. However NPCs who appear in Black Phantom form are treated as any other enemy in the stage.
Further reading: Innovative/Interesting Online Components - Demon's Souls Case Study