Swordmain

This includes sophisticated sword-fighting techniques with light and martial weapons as well as shields requiring years of basic training and proper armor. The military structure is commanded by an older, experienced Giant(ess) titled the Ironhand. The training and warring of centuries has turned these mighty Giant(esses) into artists of combat, both verbal and physical. Furthermore, the Giant trainers introduce their trainees to what little Earthpower and Stone Lore they know, which helps their apprentices to move quicker, smoother, trust in their surroundings and strike as hard as solid stone. They must also adjust their minds to face bloodshed and arduous decisions with cold internal calm. Although this Subclass was perfected by Giants, other races have trained with them learning their warring secrets; as a result, any race can follow this Archetype. 

You are most likely a Giant Seafarer, but not necessarily—particularly in the North, the various clans learned long ago that only proud fools who are more concerned for their egos than their craft turn away promising apprentices, even those of other races. If you aren’t a giant, however, you have taken a solemn oath never to take on an apprentice in this archetype: it is not for non-giants to pass on the skills of Saltheart Foamfollower's favored children. You would have no difficulty, however, finding a giant Ironhand who is willing to receive potential apprentices who came with your recommendation.

Swordmain

At 3rd level when you choose this Archetype, your Giantish training begins to unlock your Stone Lore, which is Earthpower present in all stone. This happens when you are presented with the sword and shield with which you have trained. They have both been restored and appear as if they are brand new. The only new addition, is a gem stone (DM's Choice) that is now the pommel. This gives the sword perfect balance. How this presentation takes place is also up to the DM, but it most certainly has to do with Stone Lore. 

While Earthpower is not magic in the Arcane sense, it is still magic; as a result, your sword is able to hit creatures that need a silver or magic weapon to hit. Furthermore, your familiarity with the sword allows your weapon attacks to score a critical hit on a roll of 19 or 20, but these abilities apply only to this particular weapon. If lost, you need to find or have a new weapon of the same characteristics made, and you must use it for one complete experience level before these abilities can be reapplied. 

Sword and Shield!

Starting at 7th level, while using your bonded sword and shield, you can use a reaction to smash your opponent with your shield if your opponent misses on an attack--and is in reach. If your opponent fumbles, you can use a reaction to hit that opponent with either your sword or shield (again, the foe must be in reach). Small shields deal 1d4 damage with the versatile property of 1d6. Standard shields deal 1d6 Bludgeoning Damage with the Versatile property of1d8 damage (using it two-handed). Tower Shields do 2d6 or 2d8 with Versatile Property. 

**D&D Beyond does not allow for shields to be used as a weapon. Upon choosing this Subclass, the DM will have to create a copy of your shield from a club, mace... in Homebrew, give it the appropriate AC Bonus, the Versatile Modifier, and call it a Shield.

Also, you gain a bonus to your attacks and damage while using your sword and shield, which is equal to your Wisdom modifier. This is due to unlocking more of your Stone Lore.

You can only increase either weapon to a maximum of +2 using this Earthpower ability. For example, a +2 Wisdom modifier can give both the sword and shield a +1 to attack and damage, or you can assign both points to one of the weapons. Again, you must be wielding both the sword and shield for this bonus to take effect. Any bonus you give to your shield is only for attack and damage rolls and is not added to AC. You can use this ability the number of times equal to your Constitution modifier after a Long Rest. 

Stone Lore

At 10th level, you learn to channel Earthpower from the Gemstone pommel of your sword adding damage to your rock-hard strikes. Once on each of your turns when you hit an opponent with a sword or shield attack, you can cause the attack to add and extra 1d8 Earthpower (Force) damage. When you reach 15th level, the extra damage increases to 2d8.

In addition, the Earthpower strengthens your weapon attacks so that a roll of 18–20 is a critical hit.

Earthpower

Beginnning at 15th level, Earthpower radiates from you in an aura with a 30-foot radius, awakening boldness in friendly creatures. The aura moves with you, centered on you. While in the aura, each nonhostile creature in the aura (including you) has increased Speed by 5 feet, Advantage on Initiative rolls, the ability to Move across difficult terrain made of earth or stone without spending extra movement, and deals an extra 1d8 Force (Earthpower) damage when successfully hits with a weapon attack (For you, this is the extra damage from level 10).

Stone Lore and Earthpower allows you to sense the natural ore all around you, and it warns you of unseen danger. You cannot be surprised except when incapacitated by something other than nonmagical sleep.

Stone and Earth

Starting at 18th level, Channeling your Swordmain training and Stone Lore you interpose yourself between attacks made against your allies within 15 feet until the end of your next turn. If the attack misses, you may use your Shield Smash Reaction. If the attack is a fumble, you may use either your sword or shield reaction. You can use this ability the number of times equal to your Constitution Modifier. Once gone, this ability cannot be used again until you finish a long rest.

Due to your selflessness, you can keep fighting despite grievous wounds. If you drop to 0 hit points and don't die outright, your knowledge of Stone Lore empowers you to tap into Earthpower, which allows you to make a DC 10 Constitution saving throw. If you succeed, you drop to 1 hit point instead. Each time you use this feature after the first, the DC increases by 3. When you finish a short or long rest, the DC resets to 10.

This Fighter Subclass is based on the Giants from The First, Second, and Last Chronicles of Thomas Covenant by Stephen R. Donaldson.

(Other sources. Gap into Mirrorland; Stephen R. Donaldson and the Modern Epic Vision; "THE LAND: The Chronicles of Thomas Covenant OGL"; White Dwarf #16, #21; Wikipedia: "The Chronicles of Thomas Covenant").