This axe once wielded by a mysterious creature from the Fey known simply as the Winter Knight. The blade is etched with runes of an unknown language, though one word is in a language all can read. "Auril" previous owners of the axe have speculated who Auril is but one thing is sure, this being must have been powerful. When thrown (20/60) the weapon always returns to whom it is attuned to, a dexterity check of 10 is needed to catch it.
5th level. When striking with this magic axe your target takes an additional 1d6 of cold damage, this damage ignores resistance to cold. In addition you may use your action to freeze your opponents in place, choose one target within 30 ft. that target must make a strength saving throw of 15 or be caught in your ice. At the start of each of its turns it is stuck in the ice the creature takes 2d6 cold damage.
9th level. You now gain a +1 bonus to attack and damage rolls with this axe. The axe now no longer requires a save to catch, additionally the damage of this weapon becomes 1d10 for one hand and 1d12 for two handed. You may also reroll the damage die of this weapon if you roll a 1 or 2.
13th level. You now gain a +2 bonus to attack and damage rolls with this axe instead of a +1. This weapon then awakens as a sentient weapon. The power of the storm writhes within you, you gain resistance to cold damage and based on your class you gain one of the following abilities.
Sentience: Auril the soul within the blade is neutral with an intelligence of 20, a wisdom of 15, charisma of 18. It has darkvision out to 120 ft. Auril communicates through telepathy in any language. Auril desires all the information it can obtain, seeing the far lands is its sole desire.
Fighter: Whenever you use the extra attack action each attack releases the inner storm, the first attack deals 1d6 cold, 2nd deals 1d8 lightning and the 3rd deals a 2d4 cold and lightning, and 4th attack deals 3d4s of cold and lightning.
Warden: Your connection to the sentinels of ice and lightning powers your swing. Whenever you use Warden's Grasp on a foe with this axe you deep freeze the foe, they make a dexterity save of 18 or are frozen as per the spell Deep Freeze (Deep Magic pg. 270)
Paladin: The influence of Auril mixes with the Oaths you swore to your god and unbounds your power. Whenever you smite with this weapon you deal an additional 3d8s of cold damage. If you upcast the smite this damage also increases by 1d8.
17th level. You now gain a +3 bonus to attack and damage rolls with this axe instead of a +2. Your command of the storm has peaked, you gain immunity to cold damage also you may cast the spell Blizzard as per the spell (Deep Magic pg. 268) This ability resets on the next dawn.
Proficiency with a Battleaxe allows you to add your proficiency bonus to the attack roll for any attack you make with it.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Topple. If you hit a creature with this weapon, you can force the creature to make a Constitution saving throw (DC 8 plus the ability modifier used to make the attack roll and your Proficiency Bonus). On a failed save, the creature has the Prone condition.
Notes: Warden, Fighter or Paladin, Versatile, Topple