So this may not be in your expertise, but in my setting (modern fantasy) my characters mostly fight monsters. My characters are faster than normal humans, and mostly have to use melee weapons, as monsters are resistant to normal metals, and the magical metal is too rare to reliably make bullets. I have no idea how to armor them. Speed feels like its the most important, as I can’t see how most armor could hold up to even a normal wild animal, much less one that is faster and stronger. Advice?
I don’t know what kinds of monsters your planning to throw your characters against. Enhanced reflexes would help, but, alone, it wouldn’t be enough to go into melee against anything significantly more dangerous than a human. So, if you’re fighting vampires, werewolves, or magically empowered mole men, your characters are in a bad situation.
I’d almost say the most important thing for monster hunting is practical knowledge of the creature your characters are tracking. Things like where it hides, what it feeds on, how it will behave. This becomes harder if you’re dealing with creatures possessing human levels of intelligence. Hunting a monster that is, basically, just an exotic apex predator is dangerous, but it’s something your characters can plan ahead for. Even in cases where they’re dealing with something that rivals human intellect, knowing how the creature is inclined to behave will give them a significant advantage for anticipating its actions. Remember how we’ve said, “instincts will get you killed?” Yeah, this one of those times.
Things can go wrong when you’re dealing with creatures that are significantly more experienced than your hunters, as this flips the script a bit. These aren’t the first hunters to come after this monster, and as a result, they’re the ones going through the familiar motions, and getting picked off.
Armor depends on what your character is fighting. If your characters are hunting monsters which can pass for normal humans, and have human (or better) intelligence, they can use a gun on their hunters. This is a problem for a modern vampire hunter, because while guns won’t (fully) affect the vampire, they will take down humans who come after it. Similarly, for a werewolf, if they shoot someone, that’s just a murder; however, if they wolf out, and tear someone limb from limb, now everyone knows something strange is going on, and monster hunters have more reason to come knocking. At that point, ballistic vests are your best bet. Just because you can’t shoot something doesn’t mean it can’t return the favor.
Also worth knowing, most modern armor has a shelf-life. Older kevlar vests would break down in hot and humid conditions (sort of like if you’re wearing them while being physically active for months and sweating on them.) I’m not 100% sure if this is still an issue. Additionally, taking bullets will mean you need to replace your armor. There’s also stuff like plate carriers, where you’ll need to replace the plates eventually.
In contrast, (assuming your vampires have enhanced speed and strength), sending your humans into melee combat with them is a death sentence.
So, you have a limited solution. You have melee weapons which can kill monsters. But, you still have guns, you just need to get more creative with them.
Ultraviolet (1999) did some interesting work chewing around this idea. (I’m spoiling some things here, sorry.) Because the vampires are immune to lead bullets, the vampire hunters use pressed carbon rounds to, effectively, stake vampires at range using conventional firearms. As a theme, the show presents both the vampires and vampire hunters adapting to modern technology, and using it to their advantage. I’d almost put this one as a must view for urban fantasy simply because of how it discusses monsters in the modern world.
Some other, “fun” things to remember about are dragon’s breath shotgun shells, which eject highly reactive metal strips that ignite on contact with air, essentially turning a shotgun into a sort of flamethrower.
White phosphorous is similar to dragon’s breath above, except, it’s a single bullet. Also, phosphorous is really nasty when it connects. The moisture in the wound will keep the phosphorous burning deeper into the victim, until it hits bone. This is a very horrific round, and if your characters are caught carrying around large quantities of the stuff, they’re going to have to answer some very hard questions.
Moving from borderline to straight up illegal, we’ve got high explosive rounds. There’s a lot of ways to make these. One that comes to mind is taking revolver hollowpoints, filling the tip with fulminated mercury, and waxing over it. You don’t want to use this specific example in a semi-automatic, as there’s a risk the gun will go off in your hand. In this case, it doesn’t matter if something’s resistant to metal when you’re literally detonating an explosive in them.
Bullets can also function as a delivery method. One example that comes to mind is, ironically, from Skinwalkers by Tony Hillerman. A character loads shotgun shells with bone beads, to block another’s magical abilities. (Hillerman’s novels are worth reading, but they’re murder mysteries, not urban fantasy.)
Also worth working out exactly why a monster’s resistances work. You can’t shoot a vampire because it’s already dead. So, if you make it bleed, that won’t kill it, you’re just taking away its dinner and pissing it off. However, that’s the same thing as immune. Hitting a vampire with a rifle round designed for putting down an APC might not kill it, but it should spread it around the room enough that you can put it out of your misery, before it’s back up and running.
Another option that might be worth considering are bows or crossbows with tips made from the magical material. The critical thing here is being able to retrieve the projectiles (most of the time.) This approach relies on getting the drop on the monster, which could be quite difficult if the creatures posses heightened senses.
If your characters are inhuman, themselves. If they don’t have to worry about getting shot. If they’re fast enough and strong enough to go into melee with a 9ft tall snarling deathbeast and live, then they might want to look into more archaic versions of armor that allow them to fight their foes.
It’s also possible your characters are relying on armor that mystically empowers them, (or powered armor exosuits) to level the field. In that case, the armor they wear will be dictated by the rules of their setting. If the artifact that grants your character the ability to fight monsters looks like a 17th century breastplate, then that’s what they’re going to wear.