Paladin; Oath of Secrets

[Iscarabaid]

Oath Spells:
1st: Dissonant Whispers, Disguise Self
2nd: Detect Thoughts, Silence.
3rd: Speak with Dead, Bestow Curse.
4th: Dimension Door, Confusion.
5th: Seeming, Modify Memory.

3rd Level:
Channel Divinity: Bind Speech
As an action you attempt to nullify a creature's words. On a failed Wisdom save, the creature cannot speak for one minute, and are unable to provide vocal components for spell casting, you concentrate on this effect as you would a spell. At the end of each of it's turns, the creature can use an action to attempt a save.
On a successful save, the creature cannot speak until the end of their next turn.

Channel Divinity: Beguiling Touch
When you hit a creature, and use Divine Smite on it, you can choose to forgo dealing any damage (weapon and smite included) and instead use your Channel Divinity to force the creature to make a Wisdom save. On a failure, the creature is charmed by you for one hour, they make another save with advantage if you or an ally of you deals them damage, or if they witness you or your ally attacking one of their allies.
If the full duration doesn't end early, they forget you used this ability on them.
On a successful save, you have advantage on the next charisma check you make against the target, and they forget that you used this ability on them.

7th Level: Aura of Whispers
You and any creature within 10 feet of your choice can enter a shared telepathic conversation, although you do not inherent understand a creatures languages should they be different from yours. Additionally, you can spend a spell slot to understand an additional language per spell slot level that a creature within the aura understands. This effect lasts for 10 minutes, or until you spend another spell slot.
At 18th level, the range of this aura increases to 30 feet.

15th level: Strength Within Shadows
While within dim light or darkness, you gain the following benefits:
•You can see normally in darkness, whether magical or non-magical, to a range of 120 feet.
•You can cast Greater Invisibility on yourself without expending a spell slot an amount of times equal to your Charisma Modifier.

20th Level: Warrior In Mist.
You can use an action to enter a cloudy esoteric form, you gain the following benefits for the next minute.
•You gain the effects of the Blur spell, without concentration.
•At the end of each of your turns, you can use a bonus action to obfuscate all traces of your existence as you fade into a cloud of mist.
All creatures within 30 feet of you who are able to see you must make a Wisdom save, creatures outside the 30 foot radius automatically fail.
On a fail, they are unable to perceive or sense you and effectively Blinded and Deaf to your existence until the start of your next turn, they are also unable to perceive any tracks you make, such as footprints in snow or drops of blood that originated from you.
If you attack a creature under this effect, they can use a reaction to attempt a saving throw at advantage.

Flavor/Theme
The goal was to create a Paladin that was a seeker and bearer of secrets, they would have the skills to charm, sneak, and speak with others regardless of the barriers of language. The Oath of Secrets does not have much of a focus on combat until the later levels, where their skill for subversion and deception has been mastered and weaponized. They do not have any of the more powerful stealth or utility abilities, such as Scrying, Pass Without Trace, or Legend Lore, because they are still a Paladin, and the class role of Stealth/Utility must still belong to the ranger/wizard/others.
This paladin is a martial warrior who is also adapt at working within the shadows.

[mr_stibbons]

Oath Spells:
1st: Dissonant Whispers, Disguise Self
2nd: Detect Thoughts, Silence.
3rd: Speak with Dead, Bestow Curse.
4th: Dimension Door, Confusion.
5th: Seeming, Modify Memory.

3rd Level:
Channel Divinity: Bind Speech
As an action you attempt to nullify a creature's words. On a failed Wisdom save, the creature cannot speak for one minute, and are unable to provide vocal components for spell casting, you concentrate on this effect as you would a spell. At the end of each of it's turns, the creature can use an action to attempt a save.
On a successful save, the creature cannot speak until the end of their next turn.

Channel Divinity: Beguiling Touch
When you hit a creature, and use Divine Smite on it, you can choose to forgo dealing any damage (weapon and smite included) and instead use your Channel Divinity to force the creature to make a Wisdom save. On a failure, the creature is charmed by you for one hour, they make another save with advantage if you or an ally of you deals them damage, or if they witness you or your ally attacking one of their allies.
If the full duration doesn't end early, they forget you used this ability on them.
On a successful save, you have advantage on the next charisma check you make against the target, and they forget that you used this ability on them.

7th Level: Aura of Whispers
You and any creature within 10 feet of your choice can enter a shared telepathic conversation, although you do not inherent understand a creatures languages should they be different from yours. Additionally, you can spend a spell slot to understand an additional language per spell slot level that a creature within the aura understands. This effect lasts for 10 minutes, or until you spend another spell slot.
At 18th level, the range of this aura increases to 30 feet.

15th level: Strength Within Shadows
While within dim light or darkness, you gain the following benefits:
•You can see normally in darkness, whether magical or non-magical, to a range of 120 feet.
•You can cast Greater Invisibility on yourself without expending a spell slot an amount of times equal to your Charisma Modifier.

20th Level: Warrior In Mist.
You can use an action to enter a cloudy esoteric form, you gain the following benefits for the next minute.
•You gain the effects of the Blur spell, without concentration.
•At the end of each of your turns, you can use a bonus action to obfuscate all traces of your existence as you fade into a cloud of mist.
All creatures within 30 feet of you who are able to see you must make a Wisdom save, creatures outside the 30 foot radius automatically fail.
On a fail, they are unable to perceive or sense you and effectively Blinded and Deaf to your existence until the start of your next turn, they are also unable to perceive any tracks you make, such as footprints in snow or drops of blood that originated from you.
If you attack a creature under this effect, they can use a reaction to attempt a saving throw at advantage.

Flavor/Theme
The goal was to create a Paladin that was a seeker and bearer of secrets, they would have the skills to charm, sneak, and speak with others regardless of the barriers of language. The Oath of Secrets does not have much of a focus on combat until the later levels, where their skill for subversion and deception has been mastered and weaponized. They do not have any of the more powerful stealth or utility abilities, such as Scrying, Pass Without Trace, or Legend Lore, because they are still a Paladin, and the class role of Stealth/Utility must still belong to the ranger/wizard/others.
This paladin is a martial warrior who is also adapt at working within the shadows.

I think more fluff information for the feature would certainly help. For instance, is the first channel divinity supposed to create a physical gag on a creature? Generally a creature only needs to spend an action to save if a physical construct provides the condition and needs to be overcome by effort. That would be counterintuitive with the CD requiring a wis save instead of a dex or strength save though. Probably have the creature get it's extra saves at the end of turn.

EDIT: you should also put a range and targeting restrictions on Bind Speech

Beguiling touch and aura of whispers both feel a bit clunky. If beguiling touch is supposed to be a non-combat utility effect, hitting them with your weapon makes it pretty awkward to rp. In combat, requiring giving up a weapon hit and a spell slot for charmed on save is really weak-remember that charmed targets RAW still can attack your allies. I would probably either attach some serious riders to the charm effect, or drop the smite requirement and make it subtle enough to use easily out of combat.

Aura of whispers is an effect that is given out with greater range as a first level feature for most classes. I like the telepathy, but perhaps add some kind of extra effect to make it a bit more impactful-paladin auras are generally a big deal feature. Perhaps you can use a reaction to force a creature in the aura to have disadvantage on attack rolls, or some other debuff. Maybe strip charm immunity or saving throw penalties against your enchantment spells??

Paladin capstones are generally bonus actions to activate these days, the PHB ones were a mistake. the 15th level effect looks fine, and the capstone is cool enough that I don't mind the unusual mechanics.

[Iscarabaid]

I think more fluff information for the feature would certainly help. For instance, is the first channel divinity supposed to create a physical gag on a creature? Generally a creature only needs to spend an action to save if a physical construct provides the condition and needs to be overcome by effort. That would be counterintuitive with the CD requiring a wis save instead of a dex or strength save though. Probably have the creature get it's extra saves at the end of turn.

EDIT: you should also put a range and targeting restrictions on Bind Speech

Beguiling touch and aura of whispers both feel a bit clunky. If beguiling touch is supposed to be a non-combat utility effect, hitting them with your weapon makes it pretty awkward to rp. In combat, requiring giving up a weapon hit and a spell slot for charmed on save is really weak-remember that charmed targets RAW still can attack your allies. I would probably either attach some serious riders to the charm effect, or drop the smite requirement and make it subtle enough to use easily out of combat.

Aura of whispers is an effect that is given out with greater range as a first level feature for most classes. I like the telepathy, but perhaps add some kind of extra effect to make it a bit more impactful-paladin auras are generally a big deal feature. Perhaps you can use a reaction to force a creature in the aura to have disadvantage on attack rolls, or some other debuff. Maybe strip charm immunity or saving throw penalties against your enchantment spells??

Paladin capstones are generally bonus actions to activate these days, the PHB ones were a mistake. the 15th level effect looks fine, and the capstone is cool enough that I don't mind the unusual mechanics.

Thank you for the feedback, that all makes sense

Revision
Oath Spells:
1st: Comprehend Languages, Disguise Self
2nd: Detect Thoughts, Silence.
3rd: Speak with Dead, Counterspell.
4th: Dimension Door, Confusion.
5th: Seeming, Modify Memory.

3rd Level:
Channel Divinity: Bind Speech
As an action you target a creature within 60 feet, attempting to magically nullify both the sound and meaning of their words. On a failed Wisdom save, the creature cannot speak for one minute, and is unable to provide vocal components for spell casting, you concentrate on this effect as you would a spell. At the end of each of it's turns, the creature can use an action to attempt a save.
On a successful save, the creature cannot speak until the end of their next turn.

Channel Divinity: Instant Revelation.
When you or a creature you can see within 100 feet makes a ability check or saving throw, you can use your reaction and your channel divinity to grant the creature a bonus to their result equal to twice your proficiency bonus, you must grant this revelation before you know the result of the roll.

7th Level: Aura of Whispers
You and any creature you allow within 10 feet of your choice can enter a shared telepathic conversation, all creatures can communicate with each other simultaneously, although you do not inherently understand a creatures languages should they be different from yours. Additionally, you can use a reaction when you or a creature in your aura takes psychic damage to halve the damage.
At 18th level, the range of this aura increases to 30 feet.

15th level: Strength Within Shadows
Becoming closer with the nature of the unknown and the dark, you gain the following benefits:
•You can see normally in darkness, whether magical or non-magical, to a range of 120 feet.
•While within dim light or darkness, you can cast Greater Invisibility on yourself without expending a spell slot an amount of times equal to your Charisma Modifier.

20th Level: Bearer of The First Secrets.
As an bonus action, you can push your mind to transcendent levels, imbuing yourself with a divine wealth of knowledge and power. You gain the following benefits for one minute.
• You and any creatures of your choice within your Aura of Secrets have advantage on Wisdom, Intelligence, and Charisma saves, as well as resistance to psychic damage.
• Whenever you use Divine Smite on a creature, they must take a penalty to the next attack roll or ability check they make which equals the total damage dealt by Divine Smite.
•Whenever in dim light or darkness, you can use a bonus action to teleport yourself and one other creature you're touching to another area of dim light or darkness within 60 feet. An unwilling creature must make a Charisma saving throw to resist.

Revision Thoughts
•Changed Dissonant Whispers to Comprehend Languages, because it simply makes more sense for an order of knowledge gatherers.
•Scrapped Beguiling Touch to something more team-friendly, which a paladin should always be.
•Added a albeit situational defensive option to the Aura, I feel as though the power of shared telepathic communication is strong enough utility to make up for the short range and lack of use outside of conversation.
•Changed Strength in Shadows to grant dark-vision at all times.
•Scrapped capstone, making it more in line with other paladin capstones----however I would for sure want to experiment adding the previous ability to a mist/fog focused ranger subclass

[sandmote]

The aura still seems really weak.

Perhaps allow the paladin to forcibly read another creature's thoughts if they're in the aura? And then in combat you can apply (dis)advantage on some rolls based on what the paladin learns?

[Blueiji]

From the fluff section, I get the vibe that this subclass is supposed to be about discovering and hiding secrets. Given that concept, it feels like some of the spells and class features granted don’t fit into either of those aspects.

Regarding the spells: I don’t thematically get the inclusion of Bestow Curse or Dimension Door. Neither of those spells allow one to do things related to extracting knowledge, obscuring truths, deceiving others, or preventing communication (which are the categories all the other spells fall into).

Dissonant Whispers and Confusion are also potentially a stretch, but I’m imagining they represent a Paladin of Secrets weaponing their dark knowledge by overwhelming an opponent with DARK, UNKNOWABLE SECRETS.

Regarding the class features: Beguiling Touch feels thematic for a rogue, enchanter, or manipulator—but this subclass feels less about people and more about knowledge. Since the other channel divinity ability helps inhibit the spread of secrets, perhaps Beguiling Touch could be replaced with something that helps a Paladin of Secrets acquire knowledge?

If you do decide to keep Beguiling Touch, I’d still say it could use some workshopping. As it stands, utilizing Beguiling Touch requires you first to hit with a melee attack (admittedly easier if done out of combat as a non-contested touch), then expend a spell slot to smite, then forgo ALL your damage, and spend your only use of Channel Divinity per rest—and even after all that your target still gets a save (possibly multiple saves). All this feels like way too many hoops for a Channel Divinity ability.