Runeblade

There might not be a more difficult profession than the creation of magical items. A competent enchanter could spend months or years crafting a single item, painstakingly ensuring every single detail was perfect.

Runeblades has no time for that. They have studied the glyphs and runes used by enchanters, and created an 'abridged' version of it. A wizard would look at their work and call it 'nearly incomprehensible nonsense', but Runeblades can use the faint glimmer of arcane talent in them to draw power from their Runic Inscriptions, and combine it with their martial prowess to create a weapon of immense potential power- Their signature Runeblade. 

Made with great cost and care, Runeblades are little more than average warriors without their chosen instrument in hand. However, if you ever see a fighter that wields a blade lined with glowing runes, flight might be your best option.

Inspired and based on TeddyH's Rune Knight.

Runeblade

At 3rd level, you have learned how to transform any melee weapon into a Runeblade. By spending 4 uninterrupted hours (1 Workweek and 1 Month for Legendary and Artifact weapons respectively), you can inscribe a weapon with magical runes and gems that allow you to channel certain energy through contact. This requires you to use Jeweler's Tools as well as an amount of gems and powdered silver dependent on the weapon's rarity, which are consumed in the process. The cost per rarity is: Common 100Gp, Uncommon 500Gp, Rare 1000Gp, Very Rare 2000Gp, Legendary 5000Gp, Artifact 10000Gp. Once a weapon has been transformed into a Runeblade, it cannot be undone.

In addition, because they are imperfect enchantments, only a Runeblade can activate the Runic Inscriptions. When any creature who isn't a Runeblade attempts to wield a Runeweapon, the Runic Inscriptions become inert.

When you create a Runeblade, it is only with the Runic Inscriptions you know at the time. If you gain new Runic Inscriptions after creating a Runeblade, you must repeat the transformation process on that weapon to be able to use the new Inscriptions. When updating rather than fully transforming a weapon, it costs 1/10th of the narmal amount based on rarity.

Weapons that are already enchanted can also be transformed into a Runeblade without disrupting the previous enchantment, however, the GM may impose an Arcana skill check if the selected weapon has a particularly powerful or ancient enchantment. On a failed check, the previous enchantment is permanently lost. The GM may also require special materials to turn certain weapons into Runeblades, or even rule that weapons below a certain quality cannot become Runeblades at all. 

The Runeblade always requires attunement, even if the original weapon did not. If the original weapon previously required attunement, then its attunement stands in for the Runeblade's. If an existing enchantment is lost during the process of creating a Runeblade, any previous requirements of attunement are also removed from the weapon.

In addition, you gain proficiency with Jeweler's Tools and the Arcana skill.

Edge of Arcana

At 3rd level, you have learned how to inscribe a set of runes that channel certain schools of magic through your blade, and activate them in the heat of battle.

Choose two of the Runic Inscriptions below. These will comprise the totality of your enchantments. You gain knowledge of additional Runic Inscriptions at 7th, 10th and 15th levels, and an additional use of each one at 7th and 15th level as well.

As a bonus action, you may activate one of the Runic Inscriptions on the Runeblade you wield to receive the associated enchantment. The enchantment lasts for 1 minute, and if there was already an active Runic Inscription, then the older effect ends.

In addition, attacks with your Runeblade while a Runic Inscription is active are considered magical for the purposes of damage resistance against non-magical attacks.

Blessed Blade

Your weapon hums with divine light, and almost seems to move of its own accord. Whenever you make a melee weapon attack with your Runeblade, roll 2d4 and add one of the results to your attack roll.

Brilliant Blade

Light reflects strangely off your Runeblade while this enchantment is active, refracting into a spectrum of colors at different angles. Whenever you miss with a melee weapon attack with your Runeblade, the creature that you targeted with the attack must make a Wisdom saving throw, becoming blinded until the start of their next turn on a failure.

The difficulty class for the saving throw is 8 + your proficiency bonus + your intelligence modifier.

Chromatic Carve

The glowing runes across your weapon hum brightly, changing color with each pulse. Whenever you use the Attack action, select a damage type: acid, cold, fire, lightning, poison, or thunder. Until the end of your turn, add 1d6 of the selected damage type to each successful weapon attack with your Runeblade.

At 10th level, the damage die for this ability becomes 1d8. At 15th level, it becomes 1d10.

Coiling Chains

A thin, pitch-black chain churns and wraps around your weapon while this enchantment is active. Once per turn when you hit a creature with an attack, you may attempt to bind them with the chain. That creature must make a Strength saving throw or become Restrained until the start of your next turn. The creature may use an Action to repeat the saving throw during their turn. If they succeed, the effect ends.

The difficulty class of the saving throw is 8 + your proficiency bonus + your intelligence modifier.

Displacer Drive

Time itself seems to bend around your Runeblade when this enchantment is active, temporarily slowing those that are struck by it. Creatures that take damage from your Runeblade lose -1 AC and cannot take Reactions until the beginning of your next turn. This effect can stack a number of times equal to half your proficiency bonus (rounded up).

Reaping Rake

Foul energies and an unnatural coldness seep from your weapon while this enchantment is active. Whenever you make a successful melee weapon attack, gain hit points equal to half of the total weapon damage dealt (rounded up). For the purpose of this feature "weapon damage" is defined as the damage from the weapon's die/dice plus any flat bonuses of the same damage type (IE: Strength bonus or Great Weapon Master bonus).

Shimmering Swipe

With every swing of your weapon, faint barriers are woven behind it. Each time you make a melee weapon attack with your Runeblade that hits, gain +1 AC until the beginning of your next turn. This effect can stack a number of times equal to half your proficiency bonus (rounded up).

Spell Sunder

At 7th level, you gain the ability to disrupt hostile magics with your Runeblade. When a creature within the reach of your runeblade is targeted by a spell cast by a hostile creature, you can use your Reaction to attempt to sunder it. Make an attack roll with your Runeblade to match or exceed the spell's AC, calculated below. If the spell targeted one creature and your attack is successful, they avoid all effects of the spell. If the spell's effect is an AOE, however, you cancel the effect in a sphere centered on you with a radius equal to the reach of your runeblade. In either case the spell slot is still expended.

The AC of the triggering spell is 15 + the level of spell slot used to cast the spell.

If you roll a 20 on the die for your Spell Sunder attack roll, then you also capture the spell, gaining 1 spell charge. Whenever you make an attack roll that hits, you may expend the spell charge and release the captured spell against the creature being attacked. That creature receives the effects of the spell that was sundered as if they had been targeted by it. Any necessary calculations are made using the statistics of the original caster, and if the spell's duration was concentration, then the duration is 1 round instead.

Spell Charges gained by capturing a sundered spell are lost after 1 minute.

You can use this ability a number of times per long rest equal to your proficiency bonus.

Runic Overcharge

At 10th level, you learn how to intensify the power of your runic enchantments when it counts. 

When you make a melee attack roll using a Runeblade with one or more active enchantments, you can choose to empower the enchantment(s).

If dice are rolled as part of the enchantment's effects, roll twice as many dice and use twice as many results. If a saving throw is made as part of the enchantment's effects, it is made at disadvantage. If armor class is affected as part of the enchantment's effects, double the amount. If you gain an effect equal to half of something, gain the full amount instead. 

This effect does not alleviate stack limits, and you can use it a number of times per long rest equal to your proficiency bonus.

Rune Master

Arcane Anchor

At 18th level, your runes become so powerful that you can impress your will on the weave directly.

While you have one or more active enchantments, you gain advantage on saves against spells and other magical effects. In addition, as a reaction when a creature you can see within 60ft of you targets another creature with a spell, you may change their target to you. As a part of this reaction, you may attempt to sunder the spell (this does NOT cost a use of Spell Sunder), and you capture the spell on a roll of 19 or 20 when sundering this way.

You may use the reaction portion of this feature 3 times per long rest.