The Otherworld Welfare Inc. Branch 666 is an organization that exterminates vampires. It is not a secret society - in fact, it publicly advertises its services via magazine and newspaper advertisements, and even has an official website.
It makes millions in profit annually from its online shop, which sells anti-vampire tools such as garlic spray, talismans written in chicken blood, and wooden stake-and-hammer kits. Most of its customer base buy these products for amusement purposes, and do not take them seriously.
However, the exterminators themselves take their business seriously, and move from one place to another rather than have a set base of operations.
As vampire exterminator Cargilla explains it, no-one suspects the organization of foul play precisely because their advertising is so blatant - what with 'vampire extermination' in the title, and the "infantile '666' subtitle." Had they gone with even slightly more realistic ads, they might have gotten complaints about fraud or false advertising.
The few customers who come to the organization seeking actual assistance are the ones who have been threatened by actual vampires - ones who have gone to the police or a hospital and have finally turned to the Otherworld Welfare Inc. in desperation.
Cargilla has stated that the most important part of the organization's business is getting as much money out of these particular customers as they can.
Going by the methods that Cargilla and his team use, it is likely that typical vampire exterminators associated with the Otherworld Welfare Inc. kill their vampiric targets in broad daylight, and never look at their faces. The vampires whom the company targets are usually weak ones, ones that cannot survive in the sunlight and are pushovers in the face of humans. Usually, exterminations are recorded via camera for reference and proof purposes.
One of the tools they use in exterminating a vampire is a sort of projectile gun, a messy fusion of a spear gun and a bazooka. This weapon fires a silver-covered cylinder; if fired into a surface (like the surface of a coffin) the cylinders will explode (the explosion bores a hole through the surface) and fall apart to reveal white wooden stakes, which the cylinders eject into the holes.
The stakes themselves are filled with more explosives, which ignite soon after the stakes find their mark.
Applicants to the company usually fit into two categories: fanatics obsessed with the occult, and people willing to do anything for money.