Some barbarians lose control while raging, get lost in it, others are dumb all the time, relying on their brute strength. You are neither, your rage acts as an aid to your incredible skill and wit, to your calculating genius. Your cold burning rage ain't just an expression though, and you can manifest it to freeze foes in place, a valuable tactical ability, no doubt.

Skillful Rage

At 3rd level, your rage brings great clarity, allowing you to better harness your skills while raging. You gain proficiency in 2 skills of your choice, while raging, you can twice your proficiency bonus when making ability checks using these skills. 

Hobbling Frost

Starting at 3rd level, your strikes can freeze foes, slowing their movement and damaging them. Once per turn, when you would make an attack with advantage, you can infuse the strike with frost. The attack deals an extra 1d4 cold damage, and the target’s speed is reduced by 10ft until the end of your next turn. At 6th level, the attack deals an extra 2d4 damage, an extra 3d4 damage at 10th level, and 4d4 at 14th level.

Calculated reaction

Beginning at 6th level, your rage provides clarity to more easily react to circumstances. If you take the ready action while raging, you do not need to perform the reaction before the start of your next turn. Instead, the trigger can occur any time during the same rage, and you can perform the chosen reaction.

Frosty Protection

Starting at 6th level, you have resistance to cold damage. At 14th level, this resistance becomes immunity.

 

Raging Blizzard

Cold Blazing Steel

Starting at 14th level, your rage gives such clarity to react faster than lightning. Instead of having one reaction per round, you now have 1 reaction per turn, which are lost when that turn ends. In addition, When you hit a creature with hobbling frost, they are frightened until the start of your next turn.