Defense origin

Defender sorcerers often get their start as smiths or even apprentice smiths. Forge heat, sparks, reverberating pounding of a hammer, and hard earned sweat can often move a soul to coalesce the will to manipulate the flow of magic in the world. In more extreme cases one may find themselves laying down their life to protect another and their will shapes the world around them to better their odds in doing so. 

Forge the arcane

When you choose this origin at 1st level you learn the mage armor spell and gain the ability to cast it in a different way than most. When you cast mage armor you can instead choose to create a spectral set of armor and weapon that the target is proficient with.

The armor created can be any piece of mundane armor. The armor created does not cause disadvantage on stealth checks or have a strength requirement.

The weapon created can be any mundane  melee weapon. This melee weapon can use the targets charisma modifier for attack and damage rolls instead of their strength or dexterity modifier. It can also be used as the material component for spells that require a melee weapon that has a value. The Forge the Arcane weapon can be used as a spellcasting focus.

 The armor and weapon created disappears after 1 hour and is considered magical for the purpose of overcoming resistances. You can use this feature a number of times equal to your charisma modifier. 

Heart of the anvil

When you pick this origin at your first level in this class you gain proficiency with shields and proficiency with Smith tools. Furthermore, the spirit of the anvil also combines with your spirit to make your body stronger. Every time you gain a level in this class your hp maximum increases by 1. 

Offense is the best defense

Starting at 6th level in this class you gain the green flame blade cantrip or the booming blade cantrip. You choose when you gain this feature. Furthermore, when you use your forge the arcane weapon to cast green flame blade or booming blade you may spend 2 sorcery points to alter the spell in the following manner

Green flame blade: A green flame arc spreads out in a 15ft cone as you sweep your forge the arcane weapon. Enemies in the 15ft cone are targeted by a green flame arc and spectral copies of your  forge the arcane weapon. Make a separate melee spell attack for each target in the 15ft cone. On a hit a target takes the normal weapon damage and 1d8 extra fire damage. The extra fire damage increases to 2d8 at 11th level in this class, and 3d8 at 17th.

Booming blade: A thunderous boom extends in a 30ft line from your forge the arcane weapon. Enemies within the 30ft line are targeted by  the thunderous boom and spectral copies of your forge the arcane weapon. Make a separate melee spell attack for each target in the 30ft line. On a hit a target takes the normal weapon damage and 1d8 extra thunder damage. The extra thunder damage increases to 2d8 at 11th level, and 3d8 at 17th. 

Metamagic options cannot be used on either of these class features.

Arcane smith

Starting at 14th level in this class, when you use your Forge the Arcane feature you may choose to expend up to 6 sorcery points in order to improve the quality of the armaments created. Either armor or weapon can only be improved to a +3 variant of what you decide to create and each improvement tier costs one sorcery point. Ie a +2 forge the arcane longsword and a +3 forge the arcane plate armor would cost 5 additional sorcery points with your expended use of forge the arcane. 

Defender of the damned

When you reach 18th level in this class you truly become a beacon of defense. If you know them, you may cast the shield spell and absorb elements spell at will. Furthermore, they both now have a range of 60ft and can target allies. Finally, once per turn you may use 1 sorcery point to cast either of these spells on an ally without using your reaction as your protective instinct is 2nd nature.