Path of the Blade

 This is the Giant Primal Path from the UA:Wonders of the Multiverse (slightly altered and flavoured to be a non magical version) with features from the Prismari Mage subclass from the UA: Mages of Strixhaven (also altered to be non magical) replacing the 3rd and 10th level features. 

Inspiration and goal: The goal is to make a character that plays like a Demon Slayer character would from Kimetsu no Yaiba.

Barbarians who walk the Path of the Blade learn breathing techniques to focus their rage which amplifies their physicality and inner life force(Ki). Their breathing hightens their senses and pushes their body to its limits , giving them inhuman strength and speed, as their life force swells within them. These people are usually warriors that seek to master the connection between mind,body and weapon.

During their rage, they use the full potential of this swelling energy by applying it on a variety of techniques, called weapon arts, where in some cases the energy combusts and materialzes in certain ways depending on the technique that was used.

Total Concentration Breathing

Starting at 3rd level your rage does not stem from your anger anymore, but rather by a breathing technique you use to highten your physical abilities and senses.

Total concentration. While raging you gain the following benefits:

• Choose one sensory organ. While you are raging you have advantage on Wisdom(Perception) checks that rely on that sensory organ.
• You have advantage on Dexterity(Acrobatics) checks.

Weapon Arts. When you enter your rage ,choose a style of breathing technique:

• Water Style:  As your breath gets colder and calmer, your body feels lighter and lighter as you slow down your heart rate raising the efficiency of your oxygen consumption. Your movements are characterized by their fluidity and control. 
• Fire Style: As your breath gets hotter and heavier, your body temperature sky rockets and your muscles stretch reaching their full potential. This is the pinnacle of strength and power your body can provide.
• Thunder Style: As you begin breathing rapidly ,the air of your breath sparking with electricity, only to suddenly hold your breath. Your muscles then convulge inwards getting ready to spring back to their normal shape, momentarily making you reach new heights of speed and agility.

While you are raging you can use a weapon art on each of your turns as a bonus action . You can only use weapon arts that belong to the breathing style currently chosen. Starting at 3rd level you learn the weapon arts listed below "Basic Weapon Arts" and starting at 10th level you learn the weapon arts listed below "Advanced Weapon Arts".If a weapon art requires a saving throw, your weapon art save DC is calculated as follows:

Weapon Art save DC = 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice)

Basic Weapon Arts

At 3rd level you learn three basic weapon arts, which you can use while raging. Their effects are detailed below:

• Water Style, Boreal Sweep: Until the start of your next turn, you have a bonus to your AC equal to half your proficiency bonus (rounded down) and you can move across the surface of water as if it were harmless solid ground. Additionally, when you leave a space within 5 feet of a creature, you can force that creature to make a Strength saving throw against your weapon art save DC, as you attempt to trip them. On a failed save, the creature is knocked prone. You can attempt to trip each creature only once each turn.

• Fire Style, Scorching Whirl: Once before the end of your turn, you can force each creature within 10 feet of you to make a Dexterity saving throw against your weapon art save DC,as you spin your weapon around you fiercly. On a failure, a creature takes fire damage equal to 1d4 + your proficiency modifier.

• Thunder Style, Thunderlight Rush: You take the Dash action and until the end of your turn you can use the rest of your movement only to move in a straight line, but you can move through the space of other creatures and you do not provoke opportunity attacks. If you end your turn inside a creature's space, you are pushed into the nearest unoccupied space.

Constant Concentration

At 6th level, you are now able to control the life force swelling within you while you rage much more effectively, granting you the following benefits:

Instant Weapon Art. You can now use a weapon art you know as part of the bonus action you use to enter your rage.

Life Force Manifestation. When you choose a breathing style, for the duration of your rage, your melee weapon attacks deal an extra 1d6 damage. The damage type of the extra damage is either cold, fire or thunder in correspondance to the current breathing style chosen, either Water Style, Fire Style or Thunder Style.

Advanced Weapon Arts

At 10th level you learn three advanced weapon arts, which you can use while raging. Their effects are detailed below:

• Water Style, Striking Tide: Your next melee weapon attack deals an additional 1d4 cold damage. If it hits, the target must make a Strength saving throw against your weapon art save DC. On a failed save, the target's speed is reduced by 10 feet until the end of its next turn, as ice mires it.

• Fire Style, Raging Sun: Your next melee weapon attack deals an additional 1d6 fire damage. If it hits, the target must make a Constitution saving throw against your weapon art save DC. On a failed save, the target will suffer another 1d4 fire damage at the start of its next turn, as the wound you dealt to it burns.

• Thunder Style, Thunderclap and Flash: Your next melee weapon attack deals an additional 1d4 thunder damage. If it hits, the target must make a Dexterity saving throw against your weapon art save DC. On a failed save, the target is unable to take reactions until the end of its next turn, as residual lightning shocks its form.

Impeccable Physicality

At 14th level you have mastered the breathing techniques and weapon arts you use, accomplishing the pinnacle of your physical capabilities. You gain the following benefits while raging:

Mastery over Breathing. You can now use a bonus action to choose a different breathing style. In addition, the extra damage dealt by your Life Force Manifestation feature increases to 2d6.

Mastery over Body. You gain proficiency in Dexterity saving throws if you do not already have it and when you make a Dexterity or Strength saving throw, you can treat a d20 roll of a 9 or lower as a 10.