World of Rastrios
Weapon Heirloom - An heirloom weapon takes up a special attunement slot, only one heirloom weapon can be attuned at a time. It still takes up one of your 3 normal attunement slots. Heirloom items, when attuned, can be adjusted into a specific subtype of the basic item, ie: armor, weapon, shield. So an heirloom weapon can be any type of weapon in which the wielder is proficient. Heirloom items have several levels, usually 3, that can be unlocked based off certain accomplishments, usually tied to a specific enemy type tied to the items backstory. Rare (this item requires attunement)
Shadow Ward began as a non-heirloom magical sword, with a minor life drain ability that stole a small amount of health on a critical hit. The original wielder, whose name has been lost to time, began a crusade against creatures of shadow. With each shadow defeated, the sword kept a bit of the energy it claimed, and eventually grew to become more shadow-like in feature in form. It began by granting the wielder the ability to see in any darkness. It then began to change in form, dealing necrotic damage and also granting the wielder the ability to slip into shadows. The sword's legend grew so much, that all shadow creatures, demon and undead alike, have heard tales of its power. Shadow Ward has 3 levels of power, with each "level up" requiring the defeat of a powerful shadow typed enemy: 1 - initial - Grants Darkvision, even in magical darkness 2 - Defeat a Shadow Demon - Ability to take the hide action in dim light, 3/long rest - Cast Darkness 3 - Defeat a Shadow Dragon - Once per long rest, open a portal to Shadowfell. Once per long rest, Shadow Steal - Drain magical darkness from a 5 foot space, deal 6d6 necrotic damage to any creatures within the space.