PlayStationPlus is REQUIRED!! to enable online play, as it is for all multiplayer features for the PS4.
Bloodborne's online play is similar to that of From Software's early works, the Souls series. The game can be played and completed offline, although these unique online features can be used to help or create more challenge for a player. While maintaining the overall format of a single-player game, multiplayer activity is seamlessly integrated into the world. Players can choose to help others by assisting them through an area to defeat a boss, or they can choose to invade and attempt to kill other players in their world. Interactive tombstones will reveal the last moments of another player before they died, and players can also leave notes on the ground for others to see.
When a player interacts with tombstones, they may see the death of the player who left it. They can be helpful by warning the player of dangerous areas that may be ahead.
Players are able to write notes on the ground, so that other players may read them in their own worlds. Many of these messages will inform you of nearby dangers and items, while others may be deceiving, irrelevant or comedic relief. A Notebook is required to write notes. To rate notes, the player can press the either the left side of the touch pad, fine rating, or the right side of the touch pad, bad rating, while reading the note. Notes can also be rated by viewing read messages within your Notebook. Giving a fine rating to a note gives the note placer a small HP boost.
You may see player ghosts, white phantoms of other players currently playing the game in the same area as you, which may give you hints as to how to proceed through the level.
The goal of co-op play is to work together with other hunters to traverse the area and beat the boss. Up to three hunters are allowed to join forces online to tackle challenges that may be too great for a solo player. The player initiating the cooperative session act as the host and players responding act as guests.
To summon guests, the host is required to use the Beckoning Bell and have at least one Insight. To be summoned, a guest is required to use the Small Resonant Bell.
Once players successfully defeat the boss enemy in the area they are joined to, the guests receive a bonus reward and are returned to their own game. If the guest(s) die, or leave using the Silencing Blank, the guest(s) are returned to their world and no reward is received.
Because multiplayer matchmaking is automatic and random, the host can set password for their session. Other players can enter the same password and be joined to the game. Passwords can be up to 8 letters long.
Player v. Player (PVP)
Hunters don't always have to work together. PVP allows players to face off against one another in combat, using their various weapons and acquired skill to best each other by invading another player's game.
When a host is in an area where a Chime Maiden is present, PVP invasions are possible. To invade another player, one must use the Sinister Resonant Bell. In addition, hosts can summon invaders with the Sinister Resonant Bell.
There are many online tools available to help you progress in Bloodborne. For example http://bloodbornelfg.com is a Bloodborne matchmaking site. http://bloodborne.alloyape.com/1398 is a character build simulator.