Oath of the Templar

Templars are based on the real world equivalent by the same name. The men of the Church who would go around and destroy things they considered unholy whether they be text or people themselves.

Magic in many worlds are sort of viewed as an equivalent to science. So the Templar coming to destroy arcane documents fits well thematically.

Inquisitors can play a interesting role in many worlds:

• Maybe a party member is a Templar and they have to deal with a fellow party member who is a caster of the arcane. Will they let their fear of the arcane prevent them from doing the greater good?
• Maybe a major antagonist is an Templar. They could potentially spread anti-arcane propaganda across the entire world. Making your mages feel unsafe wherever they go. Your players could argue with the Templar pointing out the hypocrisy of their use of magic to fight magic.
• Templars could make an interesting opponent for a heavy mage group as they might need to resort to other means to win a confrontation. Maybe the fighter switches to a more defensive role attempting to keep the Inquisitor away from his spellcasting allies.

Channel Divinity

When you take this Oath at 3rd level, you gain the following two Channel Divinity options.

Martial Counterspell: When a target casts a spell within your melee attack range you can spend your Channel Divinity and reaction to take an opportunity attack. If this attack lands their spell fails and their action and spell slot are wasted.

Focus Rupture: As an action, you can make a special attack with an attack bonus equal to your Charisma modifier. If the attack lands, any spell the target was concentrating on is immediately ended.

Oath Spells

You gain oath spells at the paladin levels listed.

Oath of the Inquisitor Spells

Aura of Null

Starting at 7th level, you emit an aura of magical interference. Whenever a creature casts a spell while inside your aura you may force the caster to make a charisma saving throw contested against your spell save dc. If the caster fails this save the spell fails and they can no longer cast a spell this turn. They retain their action and spell slot.

At 18th level, the range of this aura increases to 30 feet.

Eternal Watchmen

Beginning at 15th level, whenever you use your Divine Sense feature you also gain the effects of the Detect Magic spell. Detect Magic gained in this way lasts only as long as your divine sense. Thus you are unable to discern the school of magic using this method. This does not use up a spell slot.

Arcane Eradicator

At 20th level, once per long rest, as an action, you can emit an aura of anti-magic. You gain the following effects for 1 minute.

• You emit an aura of silence in a 30ft radius centered on yourself. This is effectively the Silence spell but it cannot be dispelled.
• You regain a use of Channel Divinity if it has been exhausted, and gain the ability to cast Channel Divinity at the cost of a 5th level spell slot.
• When you cast the Dispel Magic spell it is cast with advantage.