Nidastál

Nidastál is an alloy of mithril and adamantine; the perfect alloy. Formed by the immortal dwarves of Nidavellir in their forges, it is said that advanced magic isn't necessary to form this material, but all attempts to recreate it (even by other dwarven gods) have fallen short. The legendary weapons of the Aesir, the gods that reside in Ysgard, are said to all be forged from nidastál. While the material itself does not have a large suite of abilities, it is the only material perfect enough to be used by the immortal dwarves of Nidavellir; each item crafted out of it by them it is a one-of-a-kind artifact that possesses a large suite of magical powers on top of the innate strengths of the metal.

Any object crafted from nidastál is considered an artifact that requires attunement. It cannot be damaged or destroyed by any means other than the forges of Nidavellir.

Any weapon made of nidastál has a +3 bonus to attack and damage rolls, and deals 2d8 extra damage on a hit. This bonus increases to 5d8 against giants. Additionally, attacks with such a weapon against giants are made with advantage.

Armor made of nidastál grants the wearer a +3 bonus to armor class, advantage of saving throws against magical effects, resistance to damage dealt from spells or other magical effects, and resistance to any damage dealt by a giant.

As a bonus action while attuned to an object made of nidastál, you can cause it to fly to your grasp immediately, no matter the distance, as long as it is on the same plane of existence as yourself.

A one-handed melee weapon made of nidastál had the thrown property, with range of 100/400. When any weapon made of nidastál is thrown by someone attuned to it, they can cause the weapon to return to their grasp instantly after the attack (no action required).