Oath of Zeal.

The Oath of Zeal is taken by paladins consumed by hatred for a specific group or ideology. Zealots, as these paladins are sometimes called, pursue an inquisition against their enemies at all costs. They abandon compassion and honour as impediments to the more important work of ridding the world of those they deem dangerous or heretical.

Level 1 Features:

Tenants of Zeal.

The tenets of the Oath of Zeal are serious and severe, as are those paladins who choose to take them.
-Uncover Corruption. Darkness cannot abide the light of day. Wickedness must be revealed before it can be destroyed.
-Purge the Heretics. Heresy is a tumour that spread through the hearts of the innocent. Cut it out at the source.
-No Mercy. The righteous path requires unwavering conviction and unflinching resolve.
-By Any Means Necessary. There is no sacrifice too great when it comes to defeating the wicked.

Level 3 Feature:

Oath Spells.

Each oath has a list of associated spells. You gain access to these spells at the levels specified in the oath description. Once you gain access to an oath spell, you always have it prepared. Oath spells don't count against the number of spells you can prepare each day.
If you gain an oath spell that doesn't appear on the paladin spell list, the spell is nonetheless a paladin spell for you.

Channel Divinity: Mark of the Heretic.

You can use your Channel Divinity to mark a creature as a heretic. As a bonus action, choose a creature you can see within 30 feet and a weeping symbol appears on it. For the next minute, your weapon attacks against the chosen creature score a critical hit on a roll of 19 or 20, and each time the creature's turn starts you can use your reaction to make one weapon attack against it.

Channel Divinity: Inquisitor's Eye.

You can use your Channel Divinity to open your senses to hidden signs of corruption and malfeasance. As a bonus action, you grant yourself advantage on Intelligence (Investigation), Wisdom (Insight), and Wisdom (Perception) ability checks for the next 10 minutes. During this time, you can't be surprised.

Level 7 Feature:

Aura of Clarity.

Beginning at 7th level, you and friendly creatures within 10 feet of you can't be blinded while you are conscious. Additionally, creatures and objects of your choice within this range can't benefit from being invisible.
At 18th level, the range of this aura increases to 30 feet.

Level 15 Feature:

Compel Confession.

Starting at 15th level, you can cast the Zone of Truth spell without expending a spell slot. When you cast the spell with this feature, creatures who succeed on their saving throw take 1d4 psychic damage at the start of each of their turns while they remain within the affected area.

Level 20 Feature:

Apocalyptic Revelation.

At 20th level, as an action you can reveal the true nature of your enemies to all for 1 minute. During this time, you gain the following benefits:
-You have truesight out to a distance of 120 feet.
-Creatures who start their turn, or move within, 5 feet of you must make a Constitution saving throw against your paladin spell save DC. On a failure, the creature is blinded until the start of its next turn.
-As a bonus action on each of your turns you can choose a creature within 60 feet and reveal its weaknesses for all to see. Attacks made against the chosen creature have advantage until the start of your next turn.
Once you use this feature, you can't use it again until you finish a long rest.