Since the giants are slow and strong, I would recommend just running around naked. That will make your hunter extremely light and nimble and so that they can recover from their I-Frame dodge rolls quickly. Armor is of little use if the creature your fighting is both 7 times larger and stronger. Nothing is going to really protect your from one of their attacks, so armor should really just be clothes based on the environment you are hunting in.

As for the weapon, I would recommend poison. There are many lethal poisons out there that even in small doses would kill a giant. So while a drop might kill several humans, a couple more drops will kill a giant. And since they are slow, you just stab them with a needle several times (the needles size will have to vary depending on the giants skin thickness and toughness) and run away and wait for the poison to do its work.

The smart path would be to use a crossbow or longbow and to shoot the giants with poisoned arrows while on horseback (He does not have to shoot on the move. He could just kite the giants by shooting and then moving away, then shooting again).

Keep in mind that the giants would probably be able to throw rocks at him, so he would have to maintain some distance. Also, the giants are quite large, so it would take a lot of poison to kill them. The smart thing to do would be for him to have several people accompany him.

He would want to avoid melee at any cost, as even a glancing blow from a giant could smash his head in, no matter what armor he wears. Digging pit traps with feces coated stakes on the bottom and luring giants into them could be viable. Carrying some caltrops and scattering them behind him might be useful, but the giant might just walk around those. They would be quite effective at night.

Also, he might want to wear at least a gambeson. Even if it would not protect against melee strikes or thrown rocks, smarter giants might throw clay pots full of small stones at him like hand grenades, and he would want some protection from that.

Fighting one or two giants are easy, but fighting a group? that's one thing to consider.

You can't become a "Giant slayer" just because you killed one, you have to have killed a plenty.

That being said, I do think giant killer is a wrong title as your giants are WAAAAAY to strong and WAAAAY to tall for someone to kill with a blade, even with poison. At that height, the most weakest point of the giant is the feet. big, range weapons will penetrate those but they are a burden to carry by one man.

A more plausible approach might be, The Giant killing army.

Your army can, scatter long, steal spike, drench them with poison, then cover them with forestry.

Your main weapon for killing them will be ballistas... Lots of them, as they are the weapon with the highest percentage of killing a giant without any casualties.

There should be one improvement however, you ballista must have a reloading mechanism similar to a Van Helsing's repeater crossbow because you need to reload as quickly as possible, but pack a punch too.

one of your problems however, is that you got 100 persons, give or take that some of them are women, or grandparents and kids, your army lacks manpower, 50 might hold for some time.

I also suggest to be on the defensive rather than taking the fight too them, setting up traps is the best way to kill the giants, you need all the manpower to protect your people and ensure continuity of the human race.

another problem is giant carcass, yeah you killed them, but if they die close to your encampment then then stench will kill you as well, so you better plan your traps, how you set your encampment, and how you can engage the giants with your ballistas on the encampment, and during the move.

you will have a pretty busy life if you ask me...

"He is able to bend and generate magnetic fields" - Does it mean he can manipulate metal and utilize it for combat? Well... in that case "Avatar: The Last Airbender" comes to mind with metal benders (rather less accurate, meaning it's more like throwing and shooting metallic objects), or X-Man with Magneto (full, precise control), or even Irelia (special weapon) in League of Legends.

In both cases he'd carry large blades around, either swords or just the blade parts. When he fights he swings them around on range, pierces his opponents, performs attacks from their backs (when returning the blades). Against giants he would go for the weak spots, which he can reach unlike normal humans.

For armor he'd either wear leather (in case the metal interferes with his abilities if it covers his body) or an armor with metallic parts, which he can optionally use as weapons or as defence. Alternatively his armor could consist of the weapons he is carrying around, meaning the blades are part of the armor (the shoulder pads or on the backside).

Rope. Think of the AT-AT's in Star Wars, just run around it and try to trip it. Other similar things would probably work also like nets. Once it is slowed down/downed, just stick it with the pointy end.

If they are slow enough, maybe bring a large crossbow/ballista mounted on a carriage or something.

Metallic spike traps, wall or ground mounted if they can manipulated by magnetic force, depending on strength of manipulation.

Science

If there are only 100 giants around at any time, then they are at the brink of extinction. The amount of inbreeding over generations is astounding. The giants are probably stupid to the extreme due to that. Also, with only 100 giants at any time they will hardly be able to keep a culture or be educated.

Sinxe they hunt by smell, all the slayer needs to do is dressing scarecrows with clothes recently worn by actual people. Then fill the scarecrows with fresh but poisoned meat. Just wait for a few days before checking for each scarecrow.

How strong and precise magnetic field are we talking about here?

It strong enough, he can give cannon balls so much kinetic energy (preferably from distance) to massacre the poor giants to bloody equivalent of mashed potatoes.

Even worse, if can generate ridiculously strong magnetic field (like magnetars) he would be God-like, being able to distort atoms themselves in Giant bodies (and elsewhere).

In the interest of using your hero's power over magnetic fields, let's try a couple of other suggestions.

• Can he use the magnetic fields to accelerate a metal projectile beyond normal velocities? If you can take the average bow velocity of 300fps and get it up to 1200fps you could get away with something like "5 smooth ball-bearings and a sling".




• Can you manipulate a steel object at a distance? For instance, could you plant a knife somewhere in the giant's chest at range, then use magnetism to work the knife into his vitals?




• Now, to REALLY get rid of the giant, a magnetically confined Tokamak reactor...ok, off subject.




• As for armor, a magnetically controlled shield would be very entertaining. For balance, you would probably need to make the effort to your hero comparable to the force applied to it. (A giant would still knock it around)

Your main character could use a rope or net studded or made of metal. The rope wraps around the giant to bring them down, and your main character can control the movement of the rope/net very precisely by manipulating the metal in it.
Once bound, you have a number of ways to kill it; personally I would recommend just stabbing it until it bleeds out. Go for the eyes first, in case your character’s rope inexplicably fails.

For armor, I agree with others; the strength of the armor doesn't matter when going against giants, so ease of movement is key. Clothing or leather is best.