Path of the Runescarred Rager

Rare individuals possess both the willpower and the fortitude to blend ancient magic and fierce combat prowess into an art form that is both terrifying and beautiful to behold. Inflicting damage to themselves by carving long forgotten runes into their skin and tattooing arcane symbols upon their body, the Runescarred are magically enhanced and become individuals who often enjoy great respect from their clans. Through a lifetime of daily dedication, pain, and the study of ancient arcane runic lore, they seize the rage that resonates beneath their skin to give them rage-fueled innate magical abilities that enhance and expand their barbarian rage.   

As long as they have access to their rage and the blood of their enemies, their runes will imbue them with an arcane strength that cannot be denied.

 Adapted for D&D Beyond from Path of the Runescarred by Levistej

Runekeeper

A lifetime of learning and a stellar dedication towards your chosen art have rewarded you with an affinity for knowledge. Starting at 3rd level, you gain proficiency in calligrapher's tools and either the Arcana or Religion skill.

Runebound

Ancient powers resonating beneath your skin, a vast reserve of mystical energies is stored within your very being, waiting to be unleashed upon your enemies.

Starting at 3rd level, you learn three of the runes listed below and may inscribe them on your body. You may learn one new rune whenever you gain a Barbarian level if you can find someone to teach the rune to you, uncover an ancient rune text, or receive a vision of a new rune through a spiritual vision quest granted to you by your DM. 

Up to 3 runes may be prepared after a long-rest by inscribing them into your skin, causing 1 point of damage per rune inscribed. Until this damage is healed, you can activate this rune during combat while raging by smearing either your blood or the blood of your enemies upon this rune.  The activated rune glows with an angry-red light that sears away the blood from around the rune.

Once you have been damaged by an enemy, or caused damage to an enemy, spend a bonus action to activate one of your three prepared runes.  You can do this as part of your bonus action to enter a rage.  You then gain the benefits of that rune for the duration of your rage.  You can change the prepared runes activated by spending another bonus action after being damaged or damaging an enemy.  You can activate an additional rune at 6th, 10th, and 14th level.

Runes of Aptitude. You gain a bonus on all ability checks equal to your Rage damage bonus.
Runes of Elemental Fury. You Channel your Rage with elemental fury. For the duration of your rage, the power of that element crackles from your eyes and your runes. Every time you strike an opponent with a Melee attack, it must make a CON saving throw against that element. On a fail, you deal an equal amount of elemental damage as the original attack. On a success, the target suffers half damage.  There are separate runes for the elements of acid, cold, fire, lightning, or thunder. If you have multiple elemental runes for multiple elements their additional elemental damages stack.
Runes of Fortitude. You gain a bonus on all Strength, Dexterity and Constitution saving throws equal to your Rage damage bonus in hit dice.
Runes of Life Drain. When a creature within 5 feet of you is reduced to 0 hit points or suffers a critical hit, you regain a number of hit points equal to your Rage damage bonus in hit dice.
Runes of Mutual Suffering. Any creature that hits you with a melee attack immediately suffers an amount of Necrotic damage equal to your Rage damage bonus times the highest die they rolled for damage on you.
Runes of the Pack.  Igniting this Rune Channels the Strength of the Pack, and for the duration of your Rage you (and up to Two Allies within 5 Feet x your Rage Bonus) have advantage on Attack Rolls for Melee attacks. The Allies lose this boon if your Rage ends, you fall unconscious, or they are no longer within 5 Feet x your Rage Bonus of you.
Runes of Power. Any time you hit a creature with a melee weapon attack on your turn, you may push it in a straight line away from you for a number of feet equal to 5 times your Rage damage bonus.  On a critical hit, that creature is also knocked prone.
Runes of Protection. Bludgeoning, piercing, and slashing damage that you take from nonmagical weapons is reduced by an amount equal to your Rage damage bonus.
Runes of Restriction. The ground around you in a radius of feet equal to 5 times your Rage damage bonus is considered as difficult terrain for your enemies.
Runes of Swiftness. Your movement speed increases by a number of feet equal to 5 times the number listed in your Rage damage bonus and your movement doesn't provoke opportunity attacks. You also gain additional Reactions equal to your Rage damage bonus.
Runes of Warding. You may reduce any damage you take from spells and magical effects by an amount equal to your Rage damage bonus. The difficulty in the caster's attack roll is also increased by your Rage damage bonus.
Runes of Willpower. You gain a bonus on all Intelligence, Wisdom and Charisma saving throws equal to your Rage damage bonus.

Runes of Aptitude

You channel your innate rage to excel at the task at hand, gaining a bonus on all ability checks equal to your Rage damage bonus while Raging.

Runes of Elemental Fury

You Channel your Rage with elemental fury. For the duration of your rage, the power of that element crackles from your eyes and your runes. Every time you strike an opponent with a Melee attack, it must make a CON saving throw against that element. On a fail, you deal an equal amount of elemental damage as the original attack. On a success, the target suffers half damage.  There are separate runes for the elements of acid, cold, fire, lightning, or thunder. If you have multiple elemental runes for multiple elements their additional elemental damages stack.

Runes of Fortitude

You gain a bonus on all Strength, Dexterity and Constitution saving throws equal to your Rage damage bonus.

Runes of Life Drain

When a creature within 5 feet of you is reduced to 0 hit points or suffers a critical hit, you regain a number of hit points equal to your Rage damage bonus in hit dice.

Runes of Mutual Suffering

Any creature that hits you with a melee attack immediately suffers an amount of Necrotic damage equal to your Rage damage bonus times the highest die they rolled for damage on you, as the rage within you consumes them causing their flesh to blister through the point of contact.

Runes of Power

Any time you hit a creature with a melee weapon attack on your turn, you may push it in a straight line away from you for a number of feet equal to 5 times your Rage damage bonus.  On a critical hit, that creature is also knocked prone.

Runes of Protection

Bludgeoning, piercing, and slashing damage that you take from nonmagical weapons is reduced by an amount equal to your Rage damage bonus, as the Rage in you allows you to shrug off this minor damage.

Runes of Restriction

The ground around you in a radius of feet equal to 5 times your Rage damage bonus is difficult terrain for enemies

Runes of Swiftness

Your movement speed increases by a number of feet equal to 5 times the number listed in your Rage damage bonus and your movement doesn't provoke opportunity attacks.  You also gain an additional Reactions equal to your Rage Damage Bonus.

Runes of the Pack

Igniting this Rune Channels the Strength of the Pack, and for the duration of your Rage you and up to Two Allies within (5 Feet x your Rage Bonus) have advantage on Attack Rolls for Melee attacks against enemies that you are engaged with. The Allies lose this boon if your Rage ends, you fall unconscious, or they are no longer within (5 Feet x your Rage Bonus) of you.

Runes of Warding

You may reduce any damage you take from spells and magical effects by an amount equal to your Rage damage bonus. The difficulty in the caster's attack roll is also increased by your Rage damage bonus.

Runes of Willpower

You gain a bonus on all Intelligence, Wisdom and Charisma saving throws equal to your Rage damage bonus.

Runesmith

Using your own blood to inscribe ancient symbols onto cold metal, you develop an innate connection between your inner power and the weapons and armor you wield.

Beginning at 6th level, by spending at least one hour scribing runes you gain the ability to imbue magic into a weapon, shield or set of armor. When you attack with a weapon affected by this feature and you have advantage or disadvantage on the attack roll, if both the dice show the same result higher than a 1, the attack is a critical hit.

While wielding a shield or wearing armor imbued with this feature and you are the target of an attack roll that has advantage or disadvantage, if both the dice show the same result lower than 20, the attack misses.

In addition, the weapon or armor may be inscribed with one of your Runebound runes that you know.

You may have only one item imbued with this feature at a given time. If you affect a new weapon, shield or set of armor, the enchantment on your previous item ends. These items retain their magical benefits only when wielded by you.

Runescribe

Starting at 10th level, you learn 3 spells with the Ritual tag from any spell list. The spells must be of 3rd level or lower.
You may cast these spells as rituals, without providing material components. Once you use this feature to cast any of these spells a number of times equal to your Constitution modifier, you can't do so again until you finish a long rest.

Runelord

Attaining perfect equilibrium between the magic beneath your skin and your innate physical prowess, your power reaches new heights.

Starting from 14th level, you may gain the benefits of two of the runes you know whenever you use your Runebound class feature. Furthermore, you can have 2 items imbued by your Runesmith class feature at a given time.