Oath of the Harbinger

Did you ever consider playing the gigachad paladin class, but realized that he doesn't do enough to punish the beta simp goblins cumming your way with his pathetic 2 inch long, single target smite that pretends to be an attack? No male would fathom playing the avenger subclass, which is just a reskin of the oath of the ancient except it's less cool. No. You want to be the Kerberos guarding the gates of hell, the portals of wrath and terror you can unleash at a whim to flood your flaccid enemies (and allies) with death. So, as per your special order, behold! The one and only Harbinger - the Doomslayer.

 - A follower of this class promises to eradicate all traces of the profane (extraplanar entities, but usually fiendish) whenever he sees the opportunity.

 - A follower of this class must never aid or abet any of the profane, nor any who wish to aid those entities. None shall stand in your way.

 - A follower of this class must sacrifice all personal attachment, be it pleasure or even necessity, in order to wreak his wrath.

Oath Spells

You gain oath spells at the paladin levels listed.

Oath of the Harbinger Spells

Firearm Specialist

Upon taking this subclass, gain proficiency in firearms and in smiths' tools if you don't have proficiency there already. You ignore the loading property of firearms.

Channel Divinity: Sigil of DOOM

By channeling your divinity, you emblazon the sigil of your wrath (a recognizable mark, the same throughout the character's journey) onto a surface of stone or of wood. When approached within a five foot radius by a profane (extraplanar) entity, or following remote detonation at the cost of an action, the sigil will EXPLODE in purging hellfire, dealing 2d6 fire and 2d6 radiant damage per two paladin class levels (rounding up) to all creatures within a 15 foot radius of the center who fail a dexterity saving throw for half damage. You instinctively know when the sigil triggers. Only one of these sigils can be active at a time.

On detonation, you can choose to instantly expend more charges of your channel divinity to multiply the damage by that amount.

Glory Kill

 

Once per attack starting at seventh level, if you were to deal damage that would cause any enemy within arms reach of you (5 feet default) to be brought to zero hit points (this takes priority over any affects they might have that activate at that threshold), you can choose to glory-kill them instead of dealing damage normally. Doing so destroys their body beyond recognition as you tear their head from their shoulders with their organs to follow, or something similarly badass. This means that abilities that would postpone their death do not occur (even if divine/magical), they do not make death saving throws, and magic that requires a recognizable body cannot affect them. Upon glory-killing an enemy, you gain temporary HP equal to half your paladin level, rounded up, due to your DOOMpilled gameplay. You become immune to fear and charm while you have temporary HP in this way.

Starting at eleventh level, when you glory-kill an enemy, you force allies of that enemy within sixty feet of them to make a wisdom saving throw or become feared of you until the end of your next turn. You can choose at any time to root from terror any creatures affected in this way in place, preventing them from moving of their own volition. Affected creatures repeat the saving throw whenever you take damage, regaining their courage on a success.

Weapons of DOOM

Beginning at 15th level, you may choose to spend an hour out of combat to hallow a weapon to absorb your wrath. All your hallowed weapons are treated as though they are magical for the purposes of overcoming resistances, and all your magic weapons are treated as legendary for the same purpose. You may add your spellcasting modifier to all attack rolls made with hallowed weapons. Additionally, whenever an enemy is slain by a hallowed weapon or glory killed following damage from a hallowed weapon, you regain a tenth of the ammunition you had at the start of combat for that weapon, rounded up. Your hallowed firearms lose the "loading" property, or whatever it's called, the one that makes you have to take an action to reload. You are considered to be attuned to a hallowed weapon if it is a magic item that requires attunement. You can have a maximum of three hallowed at a time.

Death Incarnate

At 20th level, as an action, you take on the full aspect of the Doomslayer for an entire minute, which is extended to the next round after a glory-kill at the last round of its duration. (The aura can be extended indefinitely in this way.) You have advantage on all attack rolls, ability checks and saving throws. Your movement speed is doubled. A roll on a d20 of 18 or above on a d20 is considered a nat-20, and hence a critical hit on an attack, and a roll of a nat-1 becomes a nat-2. Your spell effects critically strike as an 18 or higher if you make an attack roll for them, and saving throws against your spell effects and your Sigil of Wrath are made with disadvantage, and critically strike as well on a saving throw role of 3 or lower. Glory-kills heal you for half your level, rounded up, in addition to their temporary HP bonus. The saving throw for your Glory Kill fear aura is also made with disadvantage. Once you use this feature, you can’t use it again until you finish a long rest. Use of this feature is extremely taxing. Once the duration ends, you fall unconscious for five minutes while retaining your temporary and current hit point pool - damage you take is first dealt to your temporary and then current hit points, and then it is dealt as though you were unconscious. Upon waking up, you have disadvantage on attack rolls, ability checks and saving throws for another minute.