Doom Guard

Fighters don't normally do things involving demons and angels, but Doom's guards are the opposite. Doom guards whole purpose in life is to eradicate any and all celestial creatures in existence until the only thing the Guards fear, is fear itself.  Filled with hatred, they found nothing but fire and rage within themselves, as they seeked vengeance against the Arch devils, Demon lords and Fallen Angels who had wronged them. Those that tasted the bite of their swords and axes named them... The Doom Guards. 

Illuminated Radiant Attacks

Beginning at 3rd level, you gain 2d4 radiant damage to all of your attacks. When you become Incapacitated, unconscious or prone, you lose the 2d4 and cannot gain it back until you finish a long rest. While you have the radiant damage, your weapon glows a faint yellow. At 6th level, it becomes a 3d4, 10th level, it becomes 2d6 and finally at 16th level, it becomes a 4d6.

Guardian of the Realm

From 3rd level onwards, you gain advantage on your first attack roll done to any aberration, Celestial, Fiend or undead. Once you use this feature 3 times, you cannot use it until you finish a short rest.

Sphere of Good and Evil

Beginning at 7th level, you can spend a bonus action to cast Protection from Good and Evil on all allied creatures within 10 feet of you. This does not require concentration and lasts for 1 minute. You cannot use this feature again until you finish a short or long rest.

Doomonic Speech

Beginning at 10th level, you learn to Read, Write and Speak Abyssal, Deep Speech and Infernal.

On Guard

Starting at 15th level, you gain two extra reactions per round, making it 3 reactions, and you gain them back on your next turn.

Slaying Legion

At 18th level, as an action you raise your weapon to the sky, striking out radiant power towards all your allies within 60 feet. All of these allies gain the bonuses from your subclass features; Illuminated Radiant Attacks and Guardian of the Realm for one minute. You can do this once per long rest.