Coldblood

A rogue of this specialization effortlessly embodies the phrase "cold blooded killer". Augmenting their stealth and combat prowess with a touch of frost magic, these intimidating warriors send chills down the spines of their foes... literally. Their magic is unique and specialized, separate from the arcane abilities of sorcerers and wizards, and can conjure effects that immobilize and disarm enemy combatants. 

Chilling Strike

At 3rd level, you learn the ray of frost cantrip. Intelligence is your spellcasting ability for it. If you already know this cantrip, you increase its damage by 1d6. Whenever you cast this cantrip, you may use your bonus action to make an attack against the same creature with a dagger, as long as it is within range.

Snowstride

Starting at 9th level, you are resistant to cold damage, and you ignore difficult terrain caused by snow or ice. Additionally, whenever you are subjected to an effect that requires you to make a saving throw to avoid cold damage, you get a +5 bonus to the roll.

Freezing Bombs

At 13th level, you have thoroughly experimented with your magic and have gained the ability to make icy traps. Using an action, you create one of these traps and throw it at a point on a floor or wall within 30 feet, where it then sticks. The trap appears as a frosty orb the size of a marble that emits a faint mist. The traps remain for 1 hour or until they are triggered. 

When a Large or smaller creature starts its turn in or enters a space within 5 feet of the trap, they become encased in an explosion of ice and are restrained. While restrained in this way, the creature is vulnerable to cold damage and resistant to fire damage. The condition lasts for 1 minute or until the creature is hit by an attack. The creature can also make a Strength saving throw with a DC equal to your Intelligence score at the start of each of their turns, ending the effect on a success. As long as you can see the trap, you can choose which creature triggers it. 

You can use this feature twice, and regain all spent uses after finishing a long rest. 

Arsenal of the Great Winter

When you reach 17th level, your frost magic gives you the power to sculpt deadly weapons from magical ice. Using an action, choose daggers, a longbow, or a longsword. Each weapon behaves like a normal version of itself, except for the details in each option. These weapons are magical, you are proficient with them, and you cannot be disarmed of them. The weapons appear in your hand, and last for 1 minute or until you dismiss them using a bonus action.

Great Winter Daggers

• When using the daggers, you may add your ability modifier to the damage of the second attack and attack twice with it using the same bonus action. 
• The daggers deal 3d4 cold damage on a hit. 
• Your walking speed increases by 10 feet until this feature ends. 
• When you hit a creature with the daggers three times in one turn, the creature's speed is reduced to 5 feet and it has disadvantage on opportunity attacks until the start of your next turn. 

Great Winter Longbow

• The bow does not require ammunition, as it creates its own. The arrows disappear when they land.
• The bow deals 3d10 cold damage on a hit. 
• Using an action, you can fire an arrow that leaves a trail of ice behind it. The trail is a line 30 feet long and 5 feet wide that can bridge gaps. For every 5 feet you and your allies move on the trail, you expend one foot of movement. It is difficult terrain for all other creatures. The trail lasts until this feature ends or until you create a new trail.

Great Winter Longsword

• The sword has the finesse property.
• The sword deals 3d8 cold damage on a hit, or 3d10 cold damage if used with two hands. 
• Once during the use of this feature, you can use your action to swing the sword in a large circle. Each creature in a 10 foot radius from you must make a Dexterity saving throw with a DC equal to your Intelligence score. On a failed save, a creature takes 4d8 cold damage and is restrained until the start of your next turn. On a successful save, the creature takes half damage and is not restrained. 

You must finish a long rest to use this feature again.