This ice-blue katana is unwieldly to hold, and can only be mastered by the most determined soldier.

You gain +3 to attack and damage rolls you make with this magic weapon, which ignores resistance to Slashing damage. On a hit, you deal an additional 1d6 Cold damage. 

Frozen Strike. When you score a critical hit with this weapon, the target must succeed on a DC 15 Constitution saving throw or be frozen in place until the end of your next turn. While frozen in this way, the target has the Incapacitated condition, and it's Speed becomes 0.

Glacial Veil. As a Magic action, you can create a 20 ft. Emanation of foggy, frost-laden air for 1 minute. For creatures other than you, the area of this Emanation is Heavily Obscured.

Frostbound Fury. When you become Bloodied, a spirit of frost within this weapon awakens. When it does, the extra Cold damage this weapon deals on a hit increases to 2d6, your Speed increases by 10 ft., and a target subjected to this weapon's Frozen Strike property is no longer allowed to make a saving throw to resist it's effects, which now lasts until the end of the target's next turn. This property lasts until you are no longer Bloodied.

Curse. This weapon is cursed - attuning to it extends it's curse to you. The weapon binds itself to you, and demands unbreakable resolve. While cursed in this way, you are unwilling to part with this weapon, and must keep it within reach at all times. If you attempt to use another weapon aside from this one, you must first make a DC 15 Wisdom saving throw. On a failure, any attack roll you make with a weapon other than this one is made with disadvantage.

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, Damage: Cold, Paladin or Fighter, Damage, Combat, Cursed, Versatile, Sap