"I charged Demois, one day, with the prospect of combining the flamebrand and the coldbrand weapons. The duality of fire and ice is a common repeating motif across many cultures, after all. This is the result of such a challenge, along with their current fixation being the switchaxe. They aren't even a ranger. They just think they're neat."

- The Vivifier

Thermodynamics is chiefly made of the red and blue metals of its respective parts, along with a series of deep gray steel accents and  parts. Body temperatures fluctuate rapidly when near the weapon. Dew and perspiration is common from the rapid heating and cooling of the air. Every time the head swaps between forms, the wielder can hear the sound of internal steam pumps and clanking gears.

Trick Weapon. The base form of the switchaxe follows the stats of the longsword. However, it does not have the versatile property, and instead has a reach of 10 ft as well as the two-handed property.

Using your item interaction (unless a specific item specifies otherwise), you can switch the switchaxe into its axe form. This form follows the stats of the battleaxe, with the two-handed and heavy properties. It always deals 1d10 damage, as you must use two hands.

Steam-Powered. You have a +1 bonus to your hit and damage rolls.

Elemental Balance. The sword form of Thermodynamics deals an additional 1d8 fire damage. The axe form of Thermodynamics deals an additional 1d8 cold damage.

Personal Infusion. Attunement to this weapon gives the wielder resistance to fire and cold damage.

Exhaust Move: A Song of Fire and Ice. Every six attacks you make with this weapon, you may use your bonus action to swing Thermodynamics, causing a miasma of ice cold mist, blue-coloured flame, and blazing hot heat to explode out from the weapon around you, temporarily creating a red and blue haze around your person. The head of the weapon to switch to its alternate form. These attacks do not "stack;" once you have hit six attacks, you cannot accrue any more, unless you use the bonus action, which resets your counter to 0.

Make an attack with Thermodynamics in its current form against a target. Regardless of whether you hit, every creature around you except yourself in a 15 ft. radius must make a DC 17 Dexterity saving throw. On a failed save, the creatures take 4d6 fire and 4d6 cold damage, and are blinded until the end of their next turn. On a successful save, they take half of the damage, and are only blinded until the start of their next turn.

Proficiencies with both battleaxes and longswords are required to effectively use this weapon.

Proficiency with a Longsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, Weapon Property: Reach, Damage: Fire, Ignore Weapon Property: Versatile, Resistance: Fire, Resistance: Cold, Versatile, Sap