Oath of Divine Reprisal

An unarmored holy warrior who posses such absolute faith in their god that they willingly accept attacks. Divine protection absorbs the punishment and transforms it into divine retaliation.

Level 3: Vessel of Faith

You use CON instead of CHA for your paladin spellcasting.
Your spell save DC becomes 8+ proficiency bonus + CON modifier
Your spell attack modifier becomes proficiency bonus + CON modifier

Level 3: Divine Body

While Unarmored your AC becomes 10+ DEX modifier + CON Modifier
Your Unarmed strikes deal 1d6 + STR or CON modifier, whichever is higher
You can use Divine Smite with unarmed strikes

Level 3: The Fool's Guard

As a bonus action you may enter a Fool's Guard stance, while in this stance:
Your AC is reduced by 2
You have advantage on saving throws against being frightened
You can make opportunity attacks with your unarmed strikes and when a creature hits you with a melee attack you can use your reaction to make an unarmed strike against that creature
At 7th level this reaction strike does not consume your reaction.

Level 3: Divine Protection

Whenever you cast a paladin spell that grants you temporary hit points those hit points are called Divine protection and grant you resistance to bludgeoning, piercing, and slashing damage from MELEE attacks.

Level 7: Faith Unbroken

While you have Divine Protection active (Temp HP from yourself) and in Fool's Guard you gain resistance to the first attack you endure each turn.
Additionally when your Divine Protection is reduced to 0 you gain normal temp HP equal to your CON modifier. note this normal temp HP is not Divine Protection

Level 15: Incarnation of Faith

As an action you become a physical manifestation of your deity for 1 minute
you gain the following

• Your size increases by one
• You gain +2 AC
• Your movement speed increases by 10 feet
• You have resistance to all damage except psychic
• You cannot be frightened, charmed, or moved
• Once during per transformation when hit by an attack you may choose to not resist the attack and the attacker makes a Constitution saving throw.
  on a failure all damage is dealt back to the attacker as radiant damage
  on a success they take half that damage
  Then you immediately regain HP equal to your CON modifier

Level 20: Faith Unquestioned

When your Divine Protection is reduced to 0 by an attack you gain Divine Protection tempHP equal to your CON modifier+your paladin level.
That creature becomes marked with "Judged" until the end of your next turn
A Judged creature takes an additional 2d8 radiant damage from your attacks and you can move 10ft towards them. If this provokes an opportunity attack you may strike back if the attack connects.

Level 3: Spells

At 3rd level you learn False Life
at 5th level you learn heroism and Martyr's Shield(functionally radiant damage Armor of Agathys)
at 9th level you learn protection from energy and Death Ward