Fantastic Armed Forces

Okay, when it comes to the Supernatural forces in general, one would think they would have some kind of law and order. After all, it makes scenes for human and maybe some animal society, there has to be some form of protection. Well, this is where these folks come in. After, society needs military or police force, in general, to keep things in check. Often times, especially need in the plot, they would have to help out the human realms for a host of reasons. Some were once human, which makes sense in when one breaks in down. Most of the time, this could be a good thing as one would need help anywhere that can found. For it comes to alignment, they're mostly Lawful Neutral since all they want is to keep stability intact.

Comic Books

 * Among the DC universe works, Martian Manhunter is often described as a police officer.
 * Rest in Peace Department evolves around an undead police force in order to protect the living from malevolent spirits.
 * The title character Hellboy pretty much prefers to protect humans as he was raised by them, resulting in him into an Ascended Demon.

Fan Works

 * Final Stand of Death has a military force and can send some of their soldiers to Earth if they have to but only if the recruits were once denizens of such. This is due to needing robotic upgrades, but pure ones weren't able to so unlike former Earth denizens. are recruited for this.

Film

 * In the Critters series, a group of extraterrestrial bounty hunters is recruited to hunt down the ravenous creatures known as the Krites.
 *  I Come in Peace has Azeck, who's part of an extraterrestrial police force assigned to track down Talec, extraterrestrial drug dealer.

Literature

 * Temeraire series has dragons in the universe. They had been domesticated and often used in as a form of the air force.

Live-Action TV

 * Host of Heaven in Supernatural is pretty much as Castiel explains that angels are actually soldiers of Heaven. Despite being jerks, most of the time, they at least their jobs.

Video Games

 * IN the Supernatural pack of The Sims 3, a Supernatural sim can be employed in a host of jobs, including law enforcement.