Champion

The Champion class will serve as the Paladin listed in the PHB, and will mechanically be nearly identical. The alterations to the existing Paladin texts are geared toward re-flavoring the Sacred Oaths. The Oath of Devotion becomes the Oath of the Liberator; the Oath of the Ancients becomes the Oath of the Wilds, and the Oath of Vengeance remains unchanged.

There are some alterations that must be done to these Oaths to make them more applicable to the Dark Sun setting, however.

Oath of the Liberator Oath of the Wilds (Ancients) Oath of Vengeance The Oath of Arcane Fealty
 * Holy Nimbus - For this feature, the Liberator gains advantage on saving throws made against Defiler magic as well as magic cast by fiends and undead. The light emitted by this spell is blue.
 * Turn the Faithless - Instead of affecting fey or fiends with their Turn the Faithless Channel Divinity feature, the spell affects willful defilers.
 * Aura of Warding - This feature only affects arcane spells
 * Elder Champion - This class feature will be renamed to Pyreen Ascension.
 * Avenging Angel - This feature will be renamed to Avangion Rebirth.

In addition to these Oaths, though, the Champion can become a Templar by selecting the Oath of Arcane Fealty. This Oath is for players who wish to play a Paladin/Champion class who is aligned with and draws strength from the sorcerer-kings of Athas. Only when following the Oath of Arcane Fealty does the Champion take a deity, with that deity being one of the Athasian sorcerer-kings; otherwise, they Champion causes exclusively. After taking this Oath, the Champion (now known as a Templar) casts as though he were an arcane caster, and his magic is considered arcane; this means he must choose between Defiling and Preserving when casting, even when casting his Paladin spells.

The Oath of Arcane Fealty has the following four tenets: Oath Spells by Champion Level - For taking the Oath of Arcane Fealty, the sorcerer-king empowers their templar with the tools necessary to locate, acquire, and/or destroy the enemies of the state. Channel Divinity Ominous Presence
 * The Price of Loyalty - No price is too high to pay for the powers granted you by your liege. You owe them everything.
 * Your Gods are Dead - There are countless cults devoted to false and dead gods in Athas, and their myths of salvation and/or redemption are as numerous as their blind followers. Crush them.
 * The Meek Shall Inherit Nothing - You were given power by your god-king, and you will give power back to them. Take what is rightfully theirs, either by strength of arm, razored wit, or arcane treachery, that you may pay them their proper tribute. No one else is deserving.
 * Life Ends, the King Endures - Life and love are not precious, for they are transient, finite, and small. The sorcerer-kings and their reach are eternal, as is their wrath.
 * 3rd - Burning Hands, Witch Bolt
 * 5th - Ray of Enfeeblement, Levitate
 * 9th - Vampiric Touch, Fear
 * 13th - Locate Creature, Blight
 * 17th - Insect Plague, Destructive Smite
 * Blight the Land - The Templar may channel divinity to intentionally despoil the surrounding tracts of land. If the landscape were previously considered high-foliage for determining the effects of Preserving and Defiling magic, it is thereafter considered low-foliage. All creatures within 30 ft of the Templar must make a Constitution save or also have their energies drained by the defiler magic. On a failed save, all creatures within the area take 1d8 damage for every 4 levels of the casting Champion (minimum 1d8), and each creature gains 2 levels of Exhaustion as detailed on page 291 of the PHB. On a successful save, creatures in the affected area take no damage, and receive only 1 level of Exhaustion.
 * Shackles of Dread - You can use your Channel Divinity to invoke your sorcerer-king's terrible name to ensnare a foe. As an action, you can cause a creature within 10 feet of you that you can see and that can hear you to quake with the fear of your sorcerer-king's wrath. The creature must succeed on a Wisdom or Charisma saving throw (its choice) or be restrained. A failed save means the creature is restrained by its fear for 5 rounds or until it is damaged. On a success, it frees itself from its fear. Creatures immune to fear effects are unaffected by Shackles of Dread.

Beginning at 7th level, enemies within 10 ft of the Templar have disadvantage on saves against fear affects. At 18th level, the area of this effect is increased to 30 ft.

Taint the Flesh

When the Templar reaches 15th level, he gains the ability to draw the vital energies for his spellcasting directly from a single, concentrated source like his sorcerer-king patron. Once/short rest, a Templar can use his bonus action to attempt to pull the life force out of a creature. To do so, he must make a successful spell attack against the creature. If the attack is successful, the creature is entitled to a Constitution saving throw (Templar's spell save DC). On a failed save, the creature takes the Templar's current Blight the Land (see above) damage as its vital energies are pulled from its body. The Templar may then use his attack action to cast a spell; if this is an attack spell, it is cast with advantage. If the attack action is not used to cast a spell, the advantage will be lost, though the creature still suffers the applicable Blight the Land damage.

If the creature make its save, it suffers one point of exhaustion, as per Blight the Land, and the Templar may still cast with advantage this round.

If the Templar misses his spell attack roll, no damage is dealt, there is no exhaustion suffered by anyone, and he does not cast with advantage this round (unless he casts with Defiler magic regardless).

There is no added benefit to both Tainting the Flesh and casting as a Defiler.

Draconic Aspect

At 20th level, you can assume several aspects of the dragon. Using your action, you undergo a transformation. For 1 hour, you gain the following benefits: Once you use this feature, you can’t use it again until you finish a long rest.
 * Leathery, reptilian wings sprout from your back and grant you a flying speed of 60 feet.
 * You emanate an aura of menace in a 30-foot radius. The first time any enemy creature enters the aura or starts its turn there during a battle, the creature must succeed on a Wisdom saving throw or become frightened of you for 1 minute or until it takes any damage. Attack rolls against the frightened creature have advantage.