you take an oath to insure that all things meet their end, whether it be the slow erosion of a deity or the destruction of an ancient city, nothing should ever last forever and these are your tenets

effervescent corosion

your smites now do your choices of acid or poison damage that treats immunity as resistance instead of radiant damage

Level 3: Oath of Corrosion Spells

The magic of your oath ensures you always have certain spells ready; when you reach a Paladin level specified in the Oath of Devotion Spells table, you thereafter always have the listed spells prepared.

Oath of Corrosion Spells

Paladin Level	Spells
3	Grease, Ray of Sickness
5	Magic Weapon, Melf's Acid Arrow
9	Stinking Cloud, Vampiric Touch
13	Blight, Vitriolic Sphere
17	Cloudkill, Insect Plague

Level 3: borrow in order to errode

When you take the attack action you can expend 1 channel divinity to summon and drench your weapon in an acidic sheen, for 2 minutes after using this feature your attacks deal extra acid damage equal to your charisma modifier.

Level 7: Aura of Effervescence

You and your allies within 15 feet have immunity to acid damage and deal 1d6 acid damage when attacking.

Level 15: Evoke Impermanence

Your magical smite now has the effects of dispel magic and can deal an additional 4d12 acid damage to creatures that have lived beyond their natural life span

Level 20: Cycle Ender

creatures that are normally immortally lose immortality and can no longer revive after being damaged by you, also any creatures you damage lose the ability to be revived or reincarnate, additionally whenever you deal acid damage you may expend a channel divinity to make that attack or action a critical.