Suicide for Hire/WMG

Suicide for Hire WMG. Beware of spoilers.

Hunter and Arcturus are each a Split Personality of the same person
Or more Freudianly, Hunter is the realistic, semi-rational, yet pleasure-seeking Ego, Arcturus the guilt-afflicted, socially concerned Super-Ego, and  the violent, self-gratifying Id.

While they nominally have separate lives during Arcturus' hiatus from their business, Hunter conspicuously doesn't do much of anything, instead sitting around their "office", buying consumer electronics and posting classified ads. These minor things - including ordering a billboard with Arcturus' face on it (albeit photoshopped) - during a period where Hunter took on no clients suggest that there may actually be no dredlocked fox in the one-man Suicide for Hire company.

Notably, most interactions with other characters involve Arcturus simply watching Hunter act out (the girl with the breast implants, the Christian protesters, etc.), or the two being treated as a unit by their clients. Only the discussions with the terminally ill patient and their illicit supplier break this pattern, with the third individual in the conversation actively treating them as two different people.
 * Not to mention said billboard listed him as "Head Mutha-F***a In Charge".

There is a supernatural force behind their success
But it's not God - it's, who is actually an entity trying to take over Arcturus' body using power gleaned from the necromantic energy released from the duo's ritualistic and terribly symbolic arranged suicides.

Hunter will become the Reaper of suicides when he shoots himself at the end
He gave the guy with the scythe a lot of work, so his punishment in death will be to take his job.
 * A Jack fan, huh?
 * Actually I got the idea from this piece of fanart.
 * Link broken.
 * Great, someone needs to tell the author that one of the thumbnails on his fanart page is broken.

Chryseis is the one spreading the word about Sf H's jobs.
She meets up with Hunter constantly, yet never has time for a date - and, the last time this happened, her job led to a woman who wanted to hire them both. She works at a hospital, and has plenty of experience with patients who genuinely want to die, for legitimate reasons... and, despite all reason to the contrary, she seems to be attracted to Hunter.
 * Oh, and she seems to be the one showing up here...

Jack is going to be royally pissed when he eventually meets Hunter.
Well, Hunter and Arc (mainly Hunter) do generate a lot of extra work for him. Work which probably wouldn't happen for decades were it not for the two Villain Protagonists. I wouldn't consider it out of the question, given the dark nature of both Suicide for Hire and Jack.

Their success is partly based on varying their methods so much.
When a serial killer is operating, he usually uses a particular MO (modus operandi/method of operation) which helps the police track them down. Hunter and Arcturus, on the other hand, vary their method with each client, which makes the pattern much less obvious. Also, the variety of their clientele helps keep them free...not all of their clients are high-school students, and they have no discernible connection to each other.