Runemaster Fighter

Specializing in the use of ancient runes, the Runemaster FIghter is able to inscribe the power of their chosen rune into their weapon, empowering the weapon and granting various abilities.  The Rune creates a tether between the Runemaster and the weapon, allowing the Runemaster ultimate control over the weapon, even after it has left their hands.  The Runes available are: Fire, Frost, Force and Lightning.  Each with their own unique properties.  

Level 3: Runic Power

You have mastered the rune type of your choice. You cannot select an additional rune type until level 15 in fighter. You can imbue a weapon with your rune to grant the ability to tether to that weapon up to 30 ft, granting additional abilities at the cost of Runic Charges. You have 4 Runic Charges which fully restore on a long rest or half as much rounded up on a short rest. Imbuing a weapon requires a full long rest cycle focused on inscribing the rune and it's power into the weapon. You can use a bonus action to recall a tethered weapon back to your hand. At this time, only one weapon can be tethered. You can expend a Runic Charge to grant the following abilities on an attack or a bonus action and a runic charge to grant the following abilities on an attack or if your weapon is impaled into an enemy:
Fire Rune: 1d8 fire damage, may engulf any unworn objects into flames.
Frost Rune: 1d8 frost damage, enemy movement speed is reduced by 10ft.
Force Rune: 1d8 force damage, enemy may be pushed or pulled 10ft, your choice.
Lightning Rune: 1d8 lightning damage, may shock those wearing metal for an additional 1d4 lightning damage,If a 4 is rolled, enemy is incapacitated until the start of their next turn.

Weapon Tether

Along with the ability to recall your tethered weapon to your hand with a bonus action, the inscribed weapon also gains the "thrown" property.  Again, the weapon tether works up to 30ft.

Level 7: Deep Runes

You have a deeper understanding of the Runes in which you draw your power from. You now gain additional abilities depending on the rune chosen. Abilities that require a saving throw will calculate as such; 8+ (STR or DEX) + proficiency modifier. This understanding also makes you proficient with Arcana checks.

Fire: Use an action and a Runic charge to burst into flames, dealing 4d6 fire damage to all within 10 ft of you. Successful dex saving throw reduces damage by half.
Frost: Use an action and a Runic charge to send a burst of frozen air from your body, freezing all within 10ft of you. Dealing 4d4 frost damage and on a failed con save, creature is frozen in place. On a successful save, movement is reduced by half for 2 rounds.
Force: Use an action and a Runic charge to send a wave of force out either pulling all within 10 ft into you or blasting all away from you. Dealing 4d4 force damage and on a failed con save, all are knocked prone. On a successful con save, all are moved 10ft toward/away from you.
Lightning: Use an action and a Runic charge to shoot lightning out to all within 10ft. They take 4d4 lightning damage and on a failed CON save are incapacitated.

Level 10: Runes of Power

Your runic charges are now d10s and add your proficiency modifier to runic charge single target damage.

Level 15: Master of Runes

Choose a second rune type to master.  With your exceptional knowledge and expertise with the runes, you know add 2 additional runic charges to your power and your runic damage is no longer affected by resistances to that type.

Level 18: Endless Runes

Whenever you roll for initiative and have no runic charges remaining, regain 1d4 charges. Also, all runic charges are d12s for single target abilities or add another damage dice for the Deep Runes abilities.