Uncanny Blade
Weapon (scimitar), rare (requires attunement)
This bizarre sword seems to be a living creature. The beak-like blade flexes and chatters from time to time incomprehensibly. The bony handle ripples rhythmically in your grasp. The four eyes peering from the guard dart around excitedly when the sword is used in combat. Whether it is sentient or not, is unknown to you. You have a +1 bonus to attack and damage rolls made with this magic weapon.
This sword bestows the ability to cast a random spell upon its wielder. Each day at dawn, roll a d4 to determine which spell the sword grants you for the day.
As an action while wielding this sword, you can cast the spell from it (save DC 15). Once the sword is used to cast a spell, it can’t be used again in this way until the next dawn. Each time you gain a character level while attuned to this sword, the die you roll to determine your daily spell increases by one (to a d6, d8, d10, and ultimately a d12). When the die increases to a d10, the sword’s save DC also increases to 16 and the sword’s bonus to attack and damage rolls increases to +2. If you end your attunement to the sword, the die resets to a d4.
Curse. This sword is actually a demon, warped into the shape of a weapon. The demon’s sentience was shattered by the magic that reshaped its body, erasing its name and its ability to communicate or form complex thoughts. Any attempt to telepathically talk to the sword will only yield a jumble of fragmented and chaotic memories. Clinging to existence, the demon siphons your life force as you grow in power. Each time you gain a level while attuned to the sword, you lose one hit die and your life span shortens by 3 years. Ending your attunement by removing this curse restores your lost hit dice and life span.