Because of this, magic items, how they are acquired and how they are treated, will be different then your average fantasy game.
The first thing you must realize is the scarcity of metal in the world. Despite being in a period called the Bronze or Iron Age, metal is still relatively uncommon and the secrets of working the material is a sacred art, with blacksmiths being seen as closer to priests then tradesman.
Because of this each weapon (and piece of armor) is seen as inherently magically. In fact, your character probably didn't purchase anything made out of metal. It was handed down to him from his father and his father before him, a blade or pendent that symbolized the bond of kin and family.
Your weapon should be an extension of your character's history and unlike in other games where your first sword will be casually tossed to the wayside when you find a newer, better model, your equipment will grow with you.
That means that the dinky sword you start out the game with could end up being a legendary +5 sword of ass-kicking by the time you retire your character. However, for this to happen, some investment has to be poured into it.
First, your weapon has to have a name.
Second is that it needs to be dedicated to a gawd. Blades anointed to the divine change when a new wielder takes them so this is a choice your character must have personally taken when they took ownership of the heirloom.
Third should be a backstory to the weapon. I recommend this being some event that will hint at the special properties of the weapon.
After this point, the growth of the weapon is linked to your character. Heroic actions and traits will rub off special properties over the course of the adventure though there is two things you should note.
Really heroic deeds beget heroic weapons. If you just sit back and let others take the risk, expect that not only will your equipment because more magical more slowly then your compatriots but that they won't gain additional cool bonuses besides simply getting a +1 to attack and damage.
Crowley's longbow, for example, might start giving him increased range in addition to pluses to hit, or Damien's sword giving its wielder a greater chance to detect lies or see illusions.
You should also be aware that these abilities will sometimes overlap with your character's abilities and not stack. For instance, I may decide to have Damien's sword's detect lie ability not augment his own.
What this means is that when that character passes on his weapon or armor, his proteges will reap the benefit. While Damien will get some use out of the sword because it'll give him a plus to attack and damage, Marian, his apprentice, will gain the real benefit, netting both the pluses and the detect lies, which may not be her class feature.
Ultimately, you will not have the final say in how your items gain magical power but there are things you can do to influence them. So far we've talked about naming your weapon and its backstory, both things will contribute how your weapon shapes up, and obviously, what your character does will have a huge impact on it as well, but your weapon will also be shaped by the gawd its dedicated to, so choose carefully.
There is one last thing you can do to direct your weapon's latent magical properties and that's through Runes. Runes are sacred symbols and letters that are scribed into an object. These tend to be one or two simply words, such as accuracy, defense, speed, and so on but they can also be complex, such as sight, or wisdom.
You may choose to use Runes or not but they should be kept to one word per weapon, shield, or armor piece.
Gaining Other Magical Items
One final note: while I have been pretty much exclusively talking about weapons gaining magical properties it is only because I didn't want to have to type out all the things that can gain powers as you gain legend.
Anything with metal in it can gain magical properties, whether that's a set of lock picks, crampons, a shield, a brush, a mirror, or even a rope with metal strands threaded into it. Additionally, armor pieces can gain individual powers or they can come together as a set and give even better bonuses.
You may also have a weapon that gains a magical property that doesn't benefit you in combat at all or a ring that gives you some heroic warrior ability.
These items don't play by different rules and so don't feel like you've gotten the shaft because you're playing a rogue and don't need a magical dagger, though they don't necessarily need a name or a backstory, they do need metal and a gawd that they're dedicated to. That will give him a heads up on which items you want to gain special properties.
Treating Magical Weapons and Armor
There is a draw back to the way magical weapons and armor are treated. It is in extremely poor taste to loot a weapon from a fallen opponent. If he was an honorable warrior, it is expected that you return his weapon to his family if possible or bury it with him. If it wasn't, it's expected that you destroy the weapon and allow the metal to return to the Shield and be purified before being forged again.
The exception to this is truly legendary equipment, like Stormcaller or Grudge, which have no family to own it and the last wielder has been dead for some time. Weapons with no owners are free game, which means that it's perfectly okay for your hero to raid ancient tombs in search of a +5 Holy Avenger and not be violating his alignment.
Shields and armor are on a case by case basis but for the most part you'll be okay looting it. though anything marked with a clan or tribe insignia should be buried or destroyed.