The Demon Slayer Corps has existed for much longer than written records, they were first organized in order to fight a small invasion from the abyss. The strongest adventurers from across Mesola came together to push back the invasion. One of these adventurers saw the terrors of demons and established an organization with the sole purpose of defeating monsters that are the most relevant threat to cities. The most powerful of these Demon slayers defeated a tarasque with the likes of the adventurers guild. They are not insanely well known, but they are one of the more respected organizations for those in power. Their headquarters is very well hidden in order to keep themselves safe from the likes of Lich, greedy tyrants, and other evils. It is theorized that they are still based in Mesola. The Demon Slayers are known for their trademark colorful blades, almost steel like, with slight differences. The metal is called "Nichirin". Though not all fighters need to use one, most demon slayers are taught a breathing technique that enhances their natural abilities. Demon Slayers rarely work in groups of more than three, the only exceptions being the Hashira meetings, and the entrance exams. Each Hashira has a personal "home base" often refereed to as a manor. They are located throughout the continent. 

Breathing Points

Breathing Styles are swordsmanship forms practiced and taught by the Demon Slayer Corps. The Breathing Styles make use of specific and concentrated breath patterns, which increase the user's lung capacity and amount of oxygen in the blood. This increase of oxygen allows the user to enhance their physical abilities and mental concentration, allowing them to fight on par with Demons, whose physical prowess surpasses that of the average human.

All known Breathing Styles currently taught within the Demon Slayer Corps are derived from Sun Breathing, the first one ever created.

The damage type relates to the Demon Slayer's chosen Breathing Style. You have a number of Breathing Points per short rest equal to your fighter level.

Saving Throws. Some of your Breathing Techniques require your target to make a saving throw to resist the Breathing Technique's effects. The saving throw DC is calculated as follows:

Breathing Save DC = 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice)

Flame: Fire
Water: Cold
Thunder: Thunder/Lightning
Wind: Thunder/Force
Love: Fire
Insect: Poison
Serpent: Acid/Poison
Mist: Force/Thunder
Beast: Slashing
Stone: Bludgeoning

Demon Slayer Senses

When you choose this archetype at 3rd level, you gain proficiency in Perception, with advantage on checks relying on hearing, smell, touch or sight.

Breathing Techniques

The Breathing Techniques are presented in alphabetical order. Each Technique uses a number of Breathing Points equals to the Technique’s number. You learn Forms 1-3 at level three, Forms 4-6 at level seven, Forms 7-9 at level 15, and Form 10 at level 18. You may use an attack to activate one of the following Techniques that you know.

1st Form

The Demon Slayer gains an additional 40ft of movement, without provoking any attacks of opportunity, before striking an opponent with a melee weapon attack. On a hit, the creature takes 2d8 damage.

2nd Form

The Demon Slayer unleashes a flurry of attacks and can use one of two attacks.
ZONE: The Demon Slayer makes a flurry of attacks in all direction, all creatures within 5ft must make a Dexterity Saving against the Demon Slayer's DC (Wisdom), or take 2d8 damage. On a save, the creature takes half damage.
SINGLE: The Demon Slayer makes a flurry of attacks against a single creature, making an additional melee weapon attack against a creature for 3d8 damage.

3rd Form

Immediately after making a weapon attack against a single creature for 4d8 damage. In addition, the Demon Slayer gains +2 to their AC until the end of their next turn.

4th Form

The Demon Slayer surrounds Themself in their element and makes a ranged attack again a foe, dealing 5d8 damage with a range of 40 feet.

5th Form

The Demon Slayer delivers a series of blows to the opponent, make 3 attack rolls, each doing 2d8 damage.

6th Form

The Demon Slayer moves rapidly to deliver blows from every direction, your movement speed increases by 30ft, and you make 2 attack rolls. If you attack from the front, you deal 1d10 damage, from behind you deal 2d10 damage.

7th Form

The Demon Slayer thrust their weapon forward, dealing 4d8 damage related to their element and 4d8 Piercing damage.

8th Form

The Demon Slayer gathers strength into their legs, you move into a space next to a target within 60ft, make an attack roll, if you hit, you will deal 5d10 damage, if you meet above half the targets ac, you will instead deal 3d10 damage.

9th Form

Final Form

You take your power to its peak, for the next 9 rounds, you will launch every single one of your forms in numerical order, if every one of them hits, you will use one final attack to deal 8d10+10 damage and gain 2 levels of exhaustion. This takes all of your remaining Breathing Points.

Slow Fall

Beginning at 7th Level, you can use your Reaction when you fall to reduce any Falling damage you take by an amount equal to five times your Fighter level.

Total Concentration Breathing: Constant

At 10th Level, for one minute: Your speed increases by 10 feet while you are not wearing armor or wielding a shield. Immediately after you take the Attack action on your turn, you can make an additional attack as a bonus action. You gain a number of temporary hit points equal to your level + your Constitution modifier (minimum of 5) for the duration of your Breathing. You gain resistance to poison damage. You gain advantage on Wisdom perception checks. If you fall unconscious whilst using Total Concentration Breathing, you can use your reaction to make your concentration check with disadvantage. On a success, you remain conscious, but prone, with 1 hit point.

Transparent World

At 15th level, on a Critical Miss, you can add a d4 to your roll. You can impose disadvantage to one attacking target as a reaction.

Demon Slayer Mark

At Level 20, you gain a demon slayer mark. Your weapons now deal radiant damage, slashing damage, or your elemental damage. A Critical hit results from a 19 or a 20