I have basically the start of a story idea forming. It takes place either during the late 1800s or early 1900s (not sure which). It's sort of a gothic horror/all myths are true setting. It's a shared universe with Frankenstein, Wolfman, Dracula, Jeckyll, and all those types of characters (not all appear, but it's fairly implied that all exist).
Right now I have 2 original characters, and I am trying to decide if they are more likely to be allies or try to kill each other.
Character 1) This character is a homunculus created for the sole purpose of combating supernatural monsters. He was created by an alchemist who would regularly capture monsters to experiment on for research. He is basically the ultimate anti-monster. His body has such a high colloidal silver content that his vary touch can burn supernatural beings. His physical abilities are well beyond that of a normal human, though not quite on level with high functioning vampires (vampires range from agile zombies to unstable superhuman serial killers to well... Dracula) or fully transformed werewolves.
Appearance: He is very slender/lightly built, relying on agility over brute strength. He has silver hair and pale silver tinted skin (I imagine him as resembling a drow/dark elf). Despite being a very lethal killer, he has very non-menacing in appearance. He is a con-artist who excels in getting people to let their guard down. He has slowed aging.
Personality: He is almost completely devoid of emotion. His opinion of humans is somewhere between admiration and jealousy, and he wishes he were human. He hunts monsters not out of any sort of malice or hate; but rather simply because it was what he was created to do. He kills all monsters, even ones that go out of their way to avoid harming humans. Despite this, he actually considers himself a monster no different from the ones he hunts. The only monster he has ever spared is Frankenstein's monster, whom he sees as too similar to himself; even referring to him as "cousin". That said, he also harbors a lot of hate and jealousy over the fact that Frankenstein's monster can feel human emotions; and will often taunt and ridicule him. Basically they are very much at odds, though neither is willing to kill the other. (also both of their creators were students at the same college)
Character 2) He is a very skilled and lethal hunter known only as "The Arcadian". His real name is Nyctimus, and he is actually of the 51 original werewolves. Unlike their spawn, the first werewolves are shifted normally, and only human during the moon (Partial moons allow them to take a very unstable human shape). This character however was given leniency by Gaia, and was given the ability to freely change his shape at will. In exchange however, he is tasked with hunting down his 49 siblings that have scattered throughout Europe and Asia.
Appearance: He has black hair and a rough beard. Unlike the above character he tall and muscular, built like a Greek warrior (well he is one). He is the character who most closely resembles the modern image of Van Helsing (the Van Helsing that exists in this world, is just a doctor with some knowlege of the occult. Like his original portrayal).
Personality: He is very stoic and anti-social. Despite being able to shapeshift at will, he rarely uses his shifted form as he sees it as barbaric/uncivilized. Unlike the above character, he is far more likely to spare monsters that don't kill or only kill humans to survive (In the latter case; it's not spare so much as not search very hard if they escape). Being immortal he tends to avoid attachment to people he knows won't live as long as him.