Besides being made of incredibly resistant materials, possess their own sentience and call it to your presence through a ''psychic link'', each weapon can use a unique ability based on their lore...
Blade of Surtr: Conjure and control the flames of Muspelheim, which are even hotter than regular flames as they can even harm gods. Don't worry, the wielder becomes resistant to the flames and heat.
Axe of Perun: Similar to Mjölnir, it allows you to control electricity at first (Developing a resistance to it) and then, learn to manipulate the weather to a certain extent (Mainly to conjure storms of all kinds).
Spear of Lugh: Upon piercing someone, it will drain all of its blood to increase its power and speed. In fact, it not well fed, the spear will target its own wielder.
Mace of Ninurta: It can summon a ''Guardian Beast'' that looks like a winged lion (As big as a school bus), who can combat at the level of some of the strongest magical beasts. If killed, the lion can be resummoned after a week of ''hibernation'' within the mace.
Cronus' Scythe: When harmed by the scythe, the injuries shall never heal and this even applies to immortal beings, negating practically all regenerative abilities.
Hades' Bident: When someone is killed by the bident, they return as a spirit that must fulfill one order given by the bident's wielder. Once the order has been fulfilled, they move on into their respective afterlifes.
However, to activate its these unique powers, you must recite a special chant and to make it more fun, you have to design your own chant. For example here's mine: ''All realms fear your flames, the end you bring is also the rebirth. Rise from your slumber, spirit of Surtr!''
As a perk offered by the weapons, when accepting one of them as your companion, they will use their magic and remold your body into a ''healthier version''. This includes removing any pre-existing ailment and retain this natural well-built body shape no matter how many calories you intake.
What do you think? What weapon did you chose?