Bastion

A Bastion is akin to a fortress, never wavering and able to take an ungodly amount of punishment in battle. They tend to wear heavy armour and wield shields, allowing them to be a frontline tank capable of dealing damage to all foes in front of them while taking all damage that is thrown their way. Whatever a Bastions battle style, you will usually find them in the thick of battle, keeping their allies safe and taking out all who stand in their way. 

Peerless Defender

Beginning when you choose this archetype at 3rd level, you learn to protect others by acting as a physical barrier against attacks. When a creature within 5 feet of you is struck by an attack, you may use your reaction to move yourself up to 5 feet and the creature up to 5 feet and become the target of the attack, potentially causing the attack to miss. You may use this feature a number of times equal to you Strength modifier, and regain all expended uses after a long rest. 

Steeled Body

Starting at 7th level, you learn to focus in on your body, granting you an increased resilience against harm. Your hit point maximum increases by twice your Fighter level. In addition, you gain an additional 2 hit points every time you gain a level in this class. 

Unstoppable

Starting at 10th level, you learn to better utilise your armour to defend yourself. While wearing heavy armour, you gain resistance to bludgeoning, piercing and slashing damage. 

Fortress Technique

Starting at 15th level, you learn to implement the fortress technique and utilise your shield in more effective ways. As a bonus action on your turn you may begin to utilise the Fortress Technique so long as you have not moved willingly on your turn. While the Fortress Technique is activated, your speed is reduced to 0, you have disadvantage on Dexterity Saving throws, you cannot be moved against your will, and you gain a +4 bonus to your AC. You may use this feature a number of times equal to your Strength modifier, regaining all expended uses after a long rest. In addition, allies within 5 feet of you reduce all bludgeoning, piercing and slashing damage they take by your proficiency bonus as long as you wield a shield and are not incapacitated. 

Unbreakable

At 18th level, your mastery of your body, armour and defensive techniques reaches its peak. You gain immunity to bludgeoning, piercing and slashing damage from non-magical attacks while you wear heavy armour. In addition, choose three damage types that aren't psychic damage. You gain resistance to those damage types while you wear heavy armour. 

Acid

You gain resistance to Acid damage while you wear heavy armour. 

Cold

You gain resistance to cold damage while you wear heavy armour

Fire

You gain resistance to fire damage while wearing heavy armour

Force

You gain resistance to force damage while wearing heavy armour.

Lightning

You gain resistance to lightning damage while wearing heavy armour.

Necrotic

You gain resistance to necrotic damage while you wear heavy armour

Radiant

You gain resistance to radiant damage while you wear heavy armour

Thunder

You gain resistance to thunder damage while wearing heavy armour.