The vanguard stands affront of the battlefield, an impassible wall of armour that forces their way through waves of enemy fire.

 

Armour Proficiency

When you are at 3rd level, you gain proficiency with heavy armour. If you already have this proficiency, you gain proficiency with one other type of artisan’s tools of your choice.

(D&D Beyond is not helping me with this, so please add the Tool Proficiency yourself if you already have proficiency with heavy armour)

 

Supercharging

Starting at 3rd level, you are able to supercharge your attacks using your spell slots. When you hit a creature with a melee weapon attack, you can expend one spell slot to deal damage to the target, in addition to the weapon’s damage. The extra damage is 2d8 for a 1st-level spell slot, plus 1d8 for each spell level higher than 1st, to a maximum of 5d8. Every long rest, you can choose one of the three different damage types for this feature: fire, lightning or thunder. The damage increases by 1d8 if the target is a construct, to a maximum of 6d8.

Electric Burst

Your supercharger feature deals lightning damage.

Overheated Attacks

Your supercharger feature deals fire damage. 

Shockwave

Your supercharger feature deals thunder damage.

 

This subclass feature does not stack with Paladin Smites.

 

Siege Weapon

Starting at 5th level, you master your favoured weapons to greater effect. You gain proficiency with one martial weapon of your choice, and when you attack with that weapon, you can use your Intelligence modifier, instead of Strength or Dexterity, for the attack and damage rolls. In addition, when you hit an object with an attack with this weapon, it deals critical damage. You gain another option at 9th level, and a third one at 15th level.

 

Extra Attack

Starting at the 5th level, you can attack twice, rather than once, whenever you take the Attack action on your turn.

 

Empowered Armour

Starting at the 9th level, while wearing medium or heavy armour you have advantage on Strength saving throws. In addition, every time you use the Supercharging feature, you gain resistance to the chosen damage type, which lasts until the start of your next turn.

 

Siege Weapon

At the 9th level, you gain another proficiency with one martial weapon of your choice, and when you attack with that weapon, you can use your Intelligence modifier, instead of Strength or Dexterity, for the attack and damage rolls. In addition, when you hit an object with an attack with this weapon, it deals critical damage. You gain another option at the 15th level.

 

Walking Fortress

Starting from the 15th level, your armour is toughed to the extent that all but the closest attacks are dampened. While wearing heavy armour you have resistance to damage caused by ranged weapon attacks.

 

Siege Weapon

At the 15th level, you gain another proficiency with one martial weapon of your choice, and when you attack with that weapon, you can use your Intelligence modifier, instead of Strength or Dexterity, for the attack and damage rolls. In addition, when you hit an object with an attack with this weapon, it deals critical damage.