Samurai, Variant (5e Subclass)
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For the archetypal samurai, battle is as much an art form as it is a test of strength. Samurai seek out challenging fights and uphold a great sense on honor in combat. A fighter who takes on the samurai subclass becomes adept at the ways of wielding two-handed weaponry.
When you choose this subclass at 3rd level, you learn special stances to increase your effectiveness in combat. You learn two stances when you gain this feature and one more of your choice at 7th, 10th and 15th level. You can use a bonus action on your turn to enter a stance if you are wielding a melee two-handed weapon. The stance lasts for 1 minute, until you change stance or until you are knocked unconscious.
Wind Stance. When you are in this stance, you may take the Disengage action as a bonus action. In addition, whenever you are hit with a ranged weapon attack while in this stance, before damage is rolled you may make an attack against the projectile (AC 16) as a reaction. On a hit, the inbound attack is instead treated as a miss and the projectile is destroyed.
Stone Stance. When you are in this stance, your AC is increased by two, but your movement reduced by half (rounded up). In addition, Enemies attacking allies other than you within 10 feet gain disadvantage on their attack
Earth Stance. While you are in this stance, you have advantage on Strength checks made to grapple and can hold a two-handed weapon in one hand whilst grappling a creature. Additionally, When you make an attack roll using strength, you may use a bonus action to gain a bonus to the damage roll equal to half your proficiency modifier (rounded down) if the attack hit. When you are subjected to an effect that allows you to make a Strength saving throw while in this stance, you may use your reaction to gain advantage on that saving throw.
Fire Stance. While in this stance, you can use a bonus action to frighten one creature within 60 feet of you that you can see. To do so, make a Charisma (Intimidation) check contested by the target's Wisdom saving throw. If you succeed, the creature is frightened until you end this stance or if it takes damage. Additionally, while in this stance you can use your reaction to dispel a single charm or fear effect that is affecting you.
Water Stance. When you successfully hit a creature with a melee weapon attack while in this stance, you may immediately spend your bonus action to attempt to knock the creature prone. If you do this, you force them to make a Dexterity saving throw equal to (8 + your Strength modifier + your proficiency bonus). Additionally, when you hit a creature with an opportunity attack while in this stance, that creatures movement is reduced to zero until the start of it's next turn.
Lightning Stance. While in this stance, you can dash as a bonus action. Additionally, while in this stance you may use your reaction to impose disadvantage on an opportunity attack targeting you.
Iai Stance. While in this stance, your AC decreases by 1. However, creatures provoke an opportunity attack from you when they enter your reach. Additionally, when you hit with a melee weapon attack on your turn while in this stance, before rolling damage you can immediately spend your bonus action to deal an additional 1d6 damage. This damage is multiplied on a critical hit.
Way of Steel
At 7th level, you have learned to master your weapon. The attack modifier for your first attack each round is doubled if you hit as long as you are attacking with a melee weapon. You also have a +1 bonus to AC when wielding a melee two-handed weapon.
Surge of Energy
At 10th level, you can use your Second Wind ability twice per short or long rest instead of once. Additionally, when you use Second Wind you also gain resistance to piercing, bludgeoning and slashing damage from non-magical weapons until the start of your next turn. Taking a stance requires no action.
Wrath of the Dragon
Beginning at 15th level you can add 5d10 to your attacks. This can be done a number of times equal to your proficiency modifier. These will be recharged after a long rest.
Starting at 18th level, you have learned to cut through anything. 3 times per long rest, whenever you use the Attack action, your melee weapon attacks have advantage until the end of your turn and score a critical hit on a roll of 17-20. Your weapon counts as adamantine for purposes of overcoming damage resistances & immunities.