Okay, I think you’ve mentally ended up in a rock, paper, scissors conflict. Which is it goes round and round until you decide one is inherently superior to the other so there’s no point in using it like rock or paper. Everyone chooses rock, right? So the best choice is paper! What’s the point of using scissors if it’s always smashed by rock? Even though scissors are still a viable option as they cut paper, they get ignored because they’re seen as less useful.
Except, scissors cuts paper. If someone comes to a match expecting their opponent to throw rock and think the best move for them is paper, then you change your move to… you guessed it. Scissors.
Right now, you’re thinking of those swords like some people think of scissors. Useless because everyone else has a rock. So step back for a moment, if your character is surrounded by people with powers and but has none of their own, they put their time in training with swords (or a variety of different weaponry, give them some credit here) then wouldn’t a part of their training also focus on dealing with people who have powers? Wouldn’t that be part of what they’re preparing for as it’s an eventual inevitability?
You have a character who is an underdog. They are absolutely at a statistical disadvantage, which is sort of the point of your story. However, if your characters are at a disadvantage, they don’t need to enter the conflict as if it’s on an even keel. If your hero cannot fight your villain then they must find a way to either:
A) Find aid to defeat them, some way to bring themselves up to their level by way of a friend helping them or through some other means. (If you’re writing a love story then it’s often the lover combining their powers with the hero to empower them.)
B) Find a way to bring the villain down to their level.
C) Subvert the villain’s advantages through some other means.
D) The hero goes to certain death, intentionally playing for time on the hopes or plan that someone more capable is going to defeat the villain.
If you can’t defeat someone conventionally, you find alternatives. If you want a “man to man” kind of fight then you build your hero and antagonist as equals where the skill difference between them is manageable or can be managed by the story.
You can build a very interesting story around a hero going on a quest or finding a way to subvert the villain’s magical powers. They might start feeling that it’s impossible and then through their journey with a side of character development realize that they either 1, don’t need to go through it alone (power of friendship), or 2, they figure out a solution to their problem that they can handle by themselves.
You have to decide that though and you need to come up with it yourself.
What you’ve created for yourself is the old analogy:
“Don’t bring a knife to a gunfight.”
And now you’re gotten stuck on it. Your hero brought a sword to a magic fight. It seems impossible when you look at it from that direction. He’s totally outmatched, right? Magic beats swords. Guns beat knives.
However, the fact is that the knife can be quite dangerous in a gunfight, most people who do don’t stand opposite at ten paces and wait for the go signal so the other guy can shoot them. They start close and attack before the guy with the gun has time to draw. Can’t use a gun if you can’t get it out of your holster. It takes time to aim and fire. If the guy with the knife starts within grabbing distance as most muggers do, already has the knife out, and closes the distance then it’s over long before it gets started.
Funny, isn’t it?
Not so much, actually. The knife/gun thing happens in real life and people have died as a result of it. A large portion of people who choose to carry a gun as a form of self-defense get caught up in the same idea you did with magic. That so long as you have the gun, it trumps other weapons. All the hours put in at the shooting range don’t help much if they haven’t been practicing point shooting, quick draws, and learning to be aware of your surroundings.
Statistics, advantages, and conventional wisdom all have their place but when they’re keeping you from stopping, sitting down, and problem solving your situation. If you’ve hit a dead end then it’s time to go back to the drawing board and your setting’s magic system. Powers and magic needs limitations, it’s easy to make it so that they can do everything but not only is that unhelpful, it’s also boring. Sit down and think about limits and weaknesses that you can put on the setting’s magic system. There’s Vancian systems like in Dungeons & Dragons for wizards where they can only perform a certain number of spells per day or ones they’ve memorized. There’s Fullmetal Alchemists’ equivalent exchange.
One of my favorites is from L.E. Modesitt Jr’s Saga of Recluce where the forces of Order and Chaos meant that you could only perform certain types of magic certain ways with nasty side effects such as headaches, backlash, and extreme hunger just for doing it, much less doing it wrong. Chaos mages, though far more aggressive and actively destructive, for example were all doomed to die young and turn to ash. Their magic aged them rapidly. Those who totally immersed themselves too much in chaos could be killed simply by coming into contact with an object created by an Order wizard and even metals commonly associated with Order could be toxic such as an iron arrowhead. Order wizards, meanwhile, build. They can live for a very, very long time if they maintain their rigid orderly lives, but order is also extremely dull. Their creations can be actively destructive, but they themselves are limited to protection. They can only work magic through objects such as a staff whereas Chaos wizards just channel. Both groups need to eat a substantial amount of food or they start to waste away as the magic they use has a direct effect on their bodies equivalent to performing strenuous exercise. They can be blinded or even killed by overdoing or channeling too much magic.
One of Starke’s favorites is Mage: the Ascension (note: not Awakening) an urban fantasy/punk rock RPG system from White Wolf which features a concept called Paradox. Mage’s world is built on a consensus reality and the power of will, if everyone believes that there is no magic then there is no magic except for that one guy over there with a lot of willpower who decides there is and is now overriding everyone else. The trick with magic and paradox is that you can do magic, so long as you don’t get caught. If you get caught doing something that shouldn’t exist according to the consensus then you receive reality backlash that makes the spell go awry. Paradox doesn’t care about your intentions, it only cares if you did it.
“Thou hast obeyed the Law. But mark well, when thou receivest good, so
equally art bound to return good threefold.” (For this is the joke in
witchcraft, the witch knows, though the initiate does not, that she will
get three times what she gave, so she does not strike hard.)
If you use a fantasy magic system in line with the Threefold Law then it’s an ethical test for your mage. You do good with your magic then you’ll receive good, but do bad or selfish acts and you will receive bad in turn.
You may not want something that costly for yourself, but it’s worth going through the fantasy section at your local library and making note of the different magic systems, the costs, and what they affect.
I’m not the biggest fan, but Jim Butcher’s Furies of Calderon starts with a protagonist who has no powers and has to live by his wits. (The first (few?) books anyway.)
So, instead of pondering your hero, ponder your setting and your villain. Once you know how both work, it often becomes easier to see the path out.