Department 4 wants to protect people. Their goal is as simple as that, whether it's to protect people from the predations of the supernatural or to protect them from the burden of knowing the truth. Department 4 fears that the truth, that the world is full of dangerous invisible creatures, would not and cannot be tolerated by humanity at large. Thus they do whatever they can, within the boundaries of the law, to keep people away from what they cannot and should not handle.
As a note, underage members of D4 typically only have access to the resources below on a case-by-case basis. Check with your fachead first.
As a government agency, the biggest resource that Department 4 has is its authority. They can get support, if limited, from local government officials and civil servants. With their ID and badges, they can gain access to various locations (within reason) and have the power to request mundane authorities to leave a particular area, if needed. Their authority also helps when dealing with media attention, and it isn't uncommon for D4 to be able to cover up an incident as something as minor as 'a gas leak'.
D4 members can requisition any kind of mundane gear (no military equipment, though, without outside authorization), and can gain access to equipment meant to deal with supernatural threats such as Shadows. Those who aren't already licensed to carry a weapon, firearm or otherwise, can get the paperwork and training they need. Yearly registration is mandatory. They also have access to special equipment for spotters, and can provide it as needed. Each branch of Department 4 also has access to a piece of equipment known as the SHU. Please see SHU for more information.
The local headquarters in Aoba Ward, Sumaru, has some useful facilities for supernatural crime-solving, including secure storage for documents and objects and a morgue. There is usually at least one car available for emergencies in the small garage. Department 4 also takes on interns, mostly from the nearby colleges.
Ideally, character concepts for Department 4 should respect and uphold the law as much as possible. 'Shady' activities are highly discouraged among its members. A listing of good character concepts for the faction follows below:
Law-abiding civil servants of various stripes; Concerned citizens of various backgrounds; Current and former military; Dedicated private detectives; Interns with an interest in the government or law; Proactive idealists.
It should be noted that Shadow-Possessed are not a good fit for this faction.
Ryotaro Dojima: A detective with the Inaba police force, Dojima might lack a Persona, but his dedication to his work allows him to be the authoritative backbone that the local branch of Department 4 needs. He provides a sense of direction for the Department through his extensive experience.
Katsuya Suou: A detective with the rank of Sergeant in Sumaru's police force, Katsuya works to see that Department 4 is kept up-to-date on recent events, and issues orders accordingly. Despite the demands of both his jobs, he makes time to investigate personally into various matters and often interacts with members of D4 directly.