Mystic Knights are great students of combat and magic. Serving as warrior-mages, they dedicate their lives to learning both the art of war and the ethereal ways of power. Also known as Spellswords, they're adept at all types of weapons and armor utilization, and are extremely versatile in combat situations.

Spellblade Casting

When you reach 3rd level, due to your training, you gain proficiency with the Arcana skill if you don't already have it.

Additionally, while many believe Mystic Knights to have magic weapons, you however know the magic flows through the individuals themselves. Using any of your spellblade imbuements requires an open hand capable of performing Somatic gestures (as though you were casting a spell) as well as the capability to provide Verbal components. For this reason many spellswords of old traditionally wielded a singular larger weapon.

Spellblade

When you reach 3rd level, you augment your martial prowess with the ability to imbue your weapons with magical effects passed down from an ancient lineage of spellswords.

Spellblade Charges.

Starting at 3rd level you can imbue your weapon with magic based on the spellblade imbuement you know. You can use this feature once. You regain expended uses when you finish a short or long rest.

Beginning at 6th level, you can use your Spellblade feature twice between rests, at 11th level you can use it three times between rests, and at 17th level, you can use it four times between rests.

Saving Throws.

Some of your imbuements require your target to make a saving throw to resist the imbuement's effects. The saving throw DC is calculated as follows:

Spellblade DC = 8 + your proficiency bonus + your Intelligence modifier

Spellblade Imbuements.

You know the Osmose spellblade imbuement, and one other spellblade imbuement of your choice, which are listed in detail below. You learn one additional spellblade imbuement of your choice at 6th, 11th, and 17th level. A weapon can only be subject to a single imbuement at any given time. You can allow an imbuement to fade at any time (no action required).

Additionally, when you gain a level in this class, you can choose one of the spellblade imbuements you know and replace it with another imbuement from the spellblade imbuements list.

Blizzard

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend one use of your spellblade charges to imbue your weapon with mystical energy that crystallizes the weapon with a frigid casing of ice. For the next 10 minutes your weapon is imbued with Blizzard. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 1d6 cold damage.

The target must make a Constitution saving throw. On a failed save, its speed is reduced by 10 feet until the start of your next turn.

This damage increases by 1d6 when you reach 9th level (2d6), and 17th level (3d6).

Drain

(11th Level Required)

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend one use of your spellblade charges to imbue your weapon with mystical energy that ignites the weapon in black and crimson shadows. For the next 10 minutes your weapon is imbued with Drain. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 1d8 necrotic damage.

Once on each of your turns when you damage a creature with Drain, you regain a number of hit points equal to the amount of necrotic damage dealt.

This damage increases by 1d8 when you reach 19th level (2d8). 

Fire

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend one use of your spellblade charges to imbue your weapon with mystical energy that ignites the weapon aflame. For the next 10 minutes your weapon is imbued with Fire. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 1d6 fire damage. 

While lit it shines bright light for 20 feet and dim light for an additional 20 feet.

This damage increases by 1d6 when you reach 9th level (2d6), and 17th level (3d6).

Flare

(17th Level Required)

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend two uses of your spellblade charges to imbue your weapon with mystical energy that envelops the weapon in transparent swirling energy. For the next 10 minutes your weapon is imbued with Flare. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 2d12 force damage.

Holy

(11th Level Required)

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend one use of your spellblade charges to imbue your weapon with mystical energy that ignites the weapon with white flames. For the next 10 minutes your weapon is imbued with Holy. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 1d8 radiant damage.

While lit it shines bright light for 20 feet and dim light for an additional 20 feet.

The damage increases by an additional 1d8 if the target is an undead or a fiend. The base damage increases by 1d8 when you reach 9th level (2d8).

Lightning

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend one use of your spellblade charges to imbue your weapon with mystical energy that ignites the weapon with crackling lightning. For the next 10 minutes your weapon is imbued with Lightning. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 1d6 lightning damage.

The target must make a Dexterity saving throw. On a failed save, it can't take reactions until the start of its next turn.

This damage increases by 1d6 when you reach 9th level (2d6), and 17th level (3d6).

Osmose

This imbuement doesn't use any charges of your Spellblade feature.

As a Bonus action, or in place of one of the attacks made with the attack action, you can imbue your weapon with mystical energy that drains the mana from a creature. For the next 10 minutes your weapon is imbued with Osmose. The next time you hit a creature with a melee weapon attack during the duration, you regain one charge of your Spellblade feature. 

You regain two charges instead when you reach 14th level.

Poison

(6th Level Required)

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend one use of your spellblade charges to imbue your weapon with mystical energy that causes the weapon to become enveloped in noxious gases. For the next 10 minutes your weapon is imbued with Poison. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 1d10 poison damage.

The target must make a Constitution saving throw. On a failed save, its poisoned for the 1 minute. At the end of each of its turns, the target can make another Constitution saving throw. On a success, the effect ends.

This damage increases by 1d10 when you reach 13th level (2d10).

Silence

(6th Level Required)

As a Bonus action, or in place of one of the attacks made with the attack action, you can expend one use of your spellblade charges to imbue your weapon with mystical energy that causes the weapon to become enveloped in Arcane runes of silencing. For the next 10 minutes your weapon is imbued with Silence. The next time you hit a creature with a melee weapon attack during the duration, you deal an additional 1d4 psychic damage. 

The target must make a Wisdom saving throw. On a failed save, it cannot speak and casting a spell that includes a verbal component is impossible for 1 minute. At the end of each of its turns, the target can make another Wisdom saving throw. On a success, the effect ends.

This damage increases by 1d4 when you reach 13th level (2d4).

Critical Shell

Beginning at 7th level, as a reaction, which you may take when you take damage from a magic effect or spell, you may use your ancient magics to impose a barrier between you and the effect. This barrier gives your resistance to the damage taken, You can use this feature once. You regain expended uses when you finish a short or long rest.

Additionally you may only use this feature when you have less than half your maximum HP remaining.

Spellsword's Strike

At 10th level, when a hostile creature's movement provokes an opportunity attack from you, you can imbue your weapon with a spellblade imbuement as part of your reaction. Imbuing in this way still requires you to expend uses of your spellblade charges as normal.

You may use this feature a number of times equal to your Intelligence modifier (minimum of 1). You regain all expended uses when you finish a long rest.

Mana Drain

At 15th level, your magic has grown to the point of becoming an extension of yourself, your capacity to drain the mana required to fuel your attacks is unparalleled.

Your weapons are permanently imbued with the Osmose spellblade imbuement unless you have another imbuement active.

Dual-cast

At 18th level, your skill as a Mystic Knight has surpassed most. You learn how to combine and control the techniques and imbuements of your order to their fullest extent. When you imbue your weapon with a spellblade imbuement, you can instead decide to combine the damage and effects of two different imbuements. This requires the normal amount of charges to imbue as if they'd been imbued separately.
You can use this feature once. You regain expended uses when you finish a short or long rest.

For example If you imbue Lightning and Blizzard, the next attack you make would deal 3d6 lightning damage, and 3d6 cold damage in addition to the weapon damage. The creature would then have to make Constitution and Dexterity saving throws against your spellblade DC and would suffer the ill effects of either imbuement seperately should they fail, as listed in the "Spellblade Imbuements" Section.