Path of The Mountains

Barbarians who walk the path of the mountains are the ones that harbor both unrelenting heat and numbing cold within their souls, unleashing these powers with their fury, embodying the mountain peaks both flaming and freezing.

 Those barbarians are often descendants of people who lived in the harshest environmental conditions, on the peak of mountaintops and within the corridors of volcanos.

Elemental Eruption

At 3rd level, your rage unleashes an eruption of elemental power, embodying either frost or flame. when you use your bonus action to rage, you can choose either Flame or Frost and gain the following benefits depending on your choice that last for the duration of your rage:-

Frost.  Cold markings cover parts of your body, coding it with Ice as large icicle shards emerge from the ground around you dealing 1d8 cold damage to everyone within 5ft of you, while in this state you gain 10 temporary hit points, additionally, when you hit the same enemy with a melee attack 4 times, the 4th attack deals an extra 2d4 cold damage and the target must make a constitution saving throw, on a failed throw, the target's movement speed is halved, this effect does not stack with multiple activations.

Flame. Red and black cracks start to appear on your skin as fire erupts from your body, dealing 1d8 fire damage to everyone within 5ft of you, while in this state your speed is increased by 10ft, additionally, when you hit the same enemy 4 times, the 4th attack deals an extra 2d4 fire damage in a 10ft cone emerging from the main target hitting them as well, everyone caught in the cone must make a dexterity saving throw, on a failed throw, taking the 2d4 damage as well and half as much on a successful one.

Mountain Walker

At 6th level, the elemental essence of frost and flame within you becomes more apparent, manifesting more often and becoming a passive part of you and granting you the following benefits

• Your movement is increased by 10ft and you gain a climbing speed equal to your walking speed.
• You gain resistance to fire or cold damage while raging depending on the element of the rage.
• You can choose the damage type of your melee attacks from the following types: the damage type of your weapon, fire, or cold.
• Your max hit points are increased by an amount equal to half your barbarian level.

Disciple of Fire and Ice

At 10th level, your elemental eruptions grow stronger as your link to the elemental powers within you becomes stronger. When entering a rage, you gain the following benefits depending on the Elemental Eruption option that you have chosen:-

Frost. While raging, you can use a bonus action to make a breath weapon attack, exhaling a freezing breeze of cold air, forcing everyone in a 15ft cone to make a dexterity saving throw, taking 2d8 cold damage on a failed save and half as much on a successful one. additionally, while in rage, as an action you can create a line of Icey spikes 5ft in width which count as difficult terrain by sacrificing your movement, and the length of that line is determined by the amount of movement sacrificed, you can choose to put more area into the width of the line over the length with your movement, if a creature spends more than one round in the area of the ice spikes they take 3d6 cold damage every round until they leave.  you can use these abilities a number of times equal to your constitution modifier, you regain all expended uses on a long rest. 

Flame. While raging, you can use a bonus action to make a breath weapon attack, spraying a blazing wave of burning flames from your mouth, forcing everyone in a 15ft cone to make a dexterity saving throw, taking 2d10 fire damage on a failed save and half as much on a successful one. additionally, while in a rage, as an action, you can create cracks within the ground 5ft in width, with magma writhing within, and slightly overflowing out of the cracks by sacrificing your movement, and the length of that line is determined by the amount of movement sacrificed, you can choose to put more area into the width of the line over the length with your movement. when a creature enters the area of the magma, they must make a dexterity saving throw, taking 2d8 fore damage on a failed throw and half as much on a successful one. you can use these abilities a number of times equal to your constitution modifier, you regain all expended uses on a long rest. 

FrostFlame Peak

At 14th level, you have gained a full understanding of the essence within you and how to unleash it fully with your fury and emotion, unlocking it's full potential and channeling it with more control. when raging, and having Elemental Eruption active, it gains the following benefits:-

Frost. 

• the initial eruption damage is increased to 3d8 cold damage
• the temporary hit points gained is increased to 20 hit points
• the damage dealt on every 4th attack while raging is increased to 4d4 cold damage
• additionally, as an action, you can end your rage by creating a small release of frost from your body, forcing every creature of your choice within 15ft to make a constitution saving throw, on a failed throw, they are stunned until the end of their next turn and their movement speed is halved, this stacks with the 4th attack of Elemental Eruption.

Flame.

• the initial eruption damage is increased to 3d8 fire damage
• the movement speed is increase is upped to 20ft 
• the damage of the 4th attack while raging is increased to 4d4 fire damage
• additionally, as an action, you can end your range by creating a small explosion of fire from your body, forcing every creature of your choice within 15ft to make a dexterity saving throw, on a failed throw, they take 5d6 fire damage and have disadvantage on their next two rolls, on a successful throw they take half of that damage.