Intention: Fighters are meant to be the “Weapon Master Class”, the one that has trained and mastered various weapons in the same vein as the Wizard, which spent years researching the training to use magic. In reality there is very little reason to use more than your starting weapon beyond when you get a magic weapon that is a straight upgrade. The goal of this subclass is to incentivise using a variety of different weapons.

TODO: Finish Slashing Damage for Level 10 ability and create level 18 ability.

At Level 3, you become apt at changing weapons to quickly respond to the situation. As part of a weapon attack, you can sheathe a weapon you are currently holding and unsheathe another weapon.

In addition, you time your actions with your party to create better openings. After you roll for initiative but before the first round of combat, you can increase or decrease your initiative up to an amount equal to your Proficiency Bonus.

At Level 3, if an enemy took bludgeoning, piercing or slashing damage from a weapon attack this round, and you hit them with a weapon attack that is different from the last instance of one of those three types of damage, you can deal an addition damage die of that weapon.

For example, If Player A hit the enemy with their Warhammer and dealt Bludgeoning damage, then Player B (The Weapon Master) hit the same enemy with a rapier, Player B would deal 2d8 Piercing damage instead of the usual 1d8. If Player B had the Extra Attack feature, they could then switch to their Battleaxe to deal 2d8 Slashing damage instead of 1d8.

At 7th Level, you can use the opening created to achieve different results. When you trigger Creating an Opening, you can choose to ignore the additional damage die and trigger an alternative effect depending on the damage type of the triggering attack. Each effect can only be triggered once per turn.

• Bludgeoning Damage: The target takes a -X penalty to any Intelligence, Wisdom or Charisma Saving Throw it makes until the end of the target's next turn, where X is the number of times you have triggered Creating an Opening this turn. The target can use an action on their turn to remove this effect.
  For Example, if you attacked thrice, first with a rapier, second with a scimitar and third with a Warhammer, and all attacks triggered Creating An Opening then the target would suffer a -3 penalty until the end of it's next turn, or if it uses an action to end the effect.
• Piercing Damage: For each weapon attack that hits after you activate this effect, and does not deal Piercing Damage, the target takes a -1 penalty to all attack rolls it makes until the end of it's next turn.
  
• Slashing Damage:

At Level 10, you can carry the momentum of your strikes through changing your weapon and into your next attack.

Whenever you make a melee weapon attack and change your weapon to a weapon with a smaller damage die with Fast Reflexes, you gain one Momentum Charge.

For example, if you switch from a Battleaxe (d8) to a Shortsword (d6) or Dagger (d4). Weapons that use more than one damage die, such as a greatsword (2d6), count as a single die.

When you make a melee weapon attack but before you roll to determine in you hit, you can use your bonus action to consume all of your Momentum Charges and apply the following effects based on the number of Momentum Charges.

• If your attack hits, increase your damage dealt by 1d4 for each Momentum Charge. If you consume at least 4 Charges increase the dice sizes to d6s. The damage type is your weapon's normal damage type.
• If you consume at least 2 Momentum Charges, you gain an extra +1 to hit for each Charge consumed. If you consume at least 6 Momentum Charges, treat half of this bonus as if you rolled it on your d20 to hit the attack.
  

For example, if you rolled a 17 on your d20 to hit and consumed 6 Momentum Charges, you would increase the 17 by 3 and treat it as of you rolled a Natural 20. You still apply the other half of the bonus as per normal.

• If at least 3 Momentum Charges are consumed, on a hit, force your opponent to make a Constitution Saving Throw (DC = 8 + The Ability Modifier used to make the attack + Proficiency Modifier). On a failed save, the target becomes dazed and must subtract 3 from any Ability Check, Attack Roll or Saving Throw it makes until the end of its next turn.

Increase the Saving DC and amount subtracted by 1 for every 3 additional Momentum Counters Consumed. If a target fails this Saving Throw more than once in a single turn, increase the amount subtracted by 1.

You lose all of your Momentum Charges at the end of your turn, or if you move more than half of your movement speed between attacks.

At Level 15, when you are attuned to at least one Magic Weapon, you can attune to up to two additional Magic Weapons, as long as all three are classified as different weapons.