Mythril

Mythril is a silvery metal that holds a mirror-like shine when polished and shows undertones of color varying by its quality. It is an exceptionally strong metal, superior to iron and steel, making it a challenge to forge even for skilled smiths. Because of its strength, mythril is highly desirable for use in making weapons and armor; a blade crafted of mythril will hold its edge for centuries. Its density is low compared to other metals, weighing roughly half that of iron of the same volume.

Regardless of its quality, white, red, black, or blue, mythril is innately attuned to the Myth, a fact which grants it the ability to channel arcane power. Because of its desirability as a material for arms and armor, the properties of mythril are most well-understood in relation to how it performs as such.   All mythril, regardless of quality, has the following properties:

• Mythril armor is exceptionally light. If a piece of armor usually imposes disadvantage on Dexterity (Stealth) checks or has a Strength requirement, the mythril version of the armor doesn't.
• Mythril weapons channel the current of arcane power into their strikes. They are considered magic weapons, and they can be used as arcane foci.

White Mythril

White mythril is the most common variety of mythril, approximately as rare as gold. Its color is a pale silver. White mythril weapons and armor have no properties beyond the standard properties of mythril arms and armor.

Red Mythril

Red mythril is the next-rarest variety of mythril. In bright light, it glints with a ruby-red shine, and it always feels cool to the touch, even in incredibly hot environments. Red mythril has the following properties, in addition to the standard properties of mythril arms and armor:

• While wearing red mythril armor, you gain a +1 bonus to armor class, and you have resistance to fire damage.
• Red mythril weapons have a +1 bonus to attack and damage rolls, and while you wield the weapon, you can use a bonus action to empower it, channeling elemental energy through the weapon. When you empower the weapon, the next attack you make with it deals an additional 1d4 fire or cold damage (your choice) on a hit.

Black Mythril

Exceptionally resilient, black mythril is the rarest variety of mythril that has a meaningful history of use. Black mythril weapons and armor have the following properties, in addition to the basic properties of mythril arms and armor:

• Black mythril armor stands strong against the toughest attacks. You gain a +2 bonus to armor class while wearing black mythril armor, and any critical hit against you becomes a normal hit.
• Black mythril weapons deliver exceptionally potent strikes. These weapons have a +2 bonus to attack and damage rolls, and when you score a critical hit with a weapon made of black mythril, the attack deals one extra die of damage.

Blue Mythril

Blue mythril is so exceptionally rare and exceptionally powerful that its properties when used as arms and armor are not particularly well-understood. Notably, blue mythril has one distinctive use outside of those functions, one so significant that it overshadows most potential desire to create arms and armor of it: magic-detecting mirrors. Through a blue mythril mirror, one can see through illusions, and the presence of magical effects is apparent as a wavering glow. Additionally, creatures of the Other, even if impeccably disguised as mortals, are revealed through a blue mythril mirror.