A paladin who has broken a vow typically seeks absolution from a cleric who shares their faith or from another paladin of the same order. The paladin might spend an all-night vigil in prayer as a sign of penitence, or undertake a fast or similar act of self-denial. After a rite of confession and forgiveness, the paladin starts fresh.
If a paladin willfully violates their oath and shows no sign of repentance, the consequences can be more serious. At the DM's discretion, an impenitent paladin might be forced to abandon this class and adopt another, or perhaps to take the Oathbreaker or Treachery paladin.
A paladin must be evil and at least 3rd level to become an Oathbreaker. The paladin replaces the features specific to their Sacred Oath with Oathbreaker features.
Oathbreaker Spells
Channel Divinity
When you take this oath at 3rd level, you gain the following two Channel Divinity options.
Control Undead: As an action, the paladin targets one undead creature they can see within 30 feet of them. The target must make a Wisdom saving throw. On a failed save, the target must obey the paladin's commands for the next 24 hours, or until the paladin uses this Channel Divinity option again. An undead whose challenge rating is equal to or greater than the paladin's level is immune to this effect.
Dreadful Aspect: As an action, the paladin channels the darkest emotions and focuses them into a burst of magical menace. Each creature of the paladin's choice within 30 feet of the paladin must make a Wisdom saving throw if it can see the paladin. On a failed save, the target is frightened of the paladin for 1 minute. If a creature frightened by this effect ends its turn more than 30 feet away from the paladin, it can attempt another Wisdom saving throw to end the effect on it.
Aura of Hate
Starting at 7th level, the paladin, as well any fiends and undead within 10 feet of the paladin, gains a bonus to melee weapon damage rolls equal to the paladin's Charisma modifier (minimum of +1). A creature can benefit from this feature from only one paladin at a time.
At 18th level, the range of this aura increases to 30 feet.
Supernatural Resistance
At 15th level, the paladin gains resistance to bludgeoning, piercing, and slashing damage from nonmagical weapons.
Dread Lord
At 20th level, the paladin can, as an action, surround themselves with an aura of gloom that lasts for 1 minute. The aura reduces any bright light in a 30-foot radius around the paladin to dim light. Whenever an enemy that is frightened by the paladin starts its turn in the aura, it takes 4d10 psychic damage. Additionally, the paladin and creatures they choose in the aura are draped in deeper shadow. Creatures that rely on sight have disadvantage on attack rolls against creatures draped in this shadow.
While the aura lasts, the paladin can use a bonus action on their turn to cause the shadows in the aura to attack one creature. The paladin makes a melee spell attack against the target. If the attack hits, the target takes necrotic damage equal to 3d10 + the paladin's Charisma modifier.
After activating the aura, the paladin can't do so again until they finish a long rest.