Entropy is the enemy that destroys us all, no matter how we fight. Everything will eventually succumb to dust, so why not join the winning side for once?

Most Mordants wield acidic or alkali substances whose properties range from “realistic chemistry” to “hollywood magic substance”, but any effect that disintegrates a target falls into their wheelhouse. The Dissolving condition is noteworthy as taking a much longer time to actually harm or kill its subject than many others, but it carries a powerful and lingering debuff effect.

Mordant Wield corrosion.
caret-right Disposal Melt things into slag.
caret-right Insoluble You're immune, your conditions aren't.
caret-right Reintegration Heal as others are harmed.
caret-right Ruination Destroy their inventory.
caret-right Slough It drips off you.

Mordant

Offense plus-circleAcid Spray: As an action, you may inflict the Dissolving condition on any subject within throwing range (0-10 meters).

minus-circleWeaponized: This ability suffers failure chances from cover, concealment, and size differences between yourself and your target just like weapon attacks do.

minus-circleSupplies: Roll a trigger die when inflicting the Dissolving condition this way. If the result is 1-3, then doing so costs 1 Supplies. You cannot use this ability if you have no Supplies remaining.
Offense plus-circleDisintegration Ray: You know how to enhance your weapons with corrosive material. Whenever you make any weapon attack and the trigger die is 10+, you inflict the Dissolving condition to your target in addition to all of that attack's normal effects (damage, conditions, etc).

minus-circleMonoelemental: Your weapon attacks can only inflict a single elemental condition on a 10+ at a time. If you have levels in multiple elemental archetypes, you pick which condition your 10+ trigger die attacks inflict each time.
Condition Explanation
broken-skull Dissolving minus-circle At the end of each round, lose one point from a combat rating of your choice (Melee, Remote, or Whelm). If all combat ratings are 0, lose 1 Flesh instead. Successfully throwing off the condition prevents combat rating decay/damage for that round.

minus-circle Combat ratings return to normal at end of current exploration turn.

Disposal

Offense plus-circleCleaning Up The Mess: When you strike the killing blow on any creature, you may choose for that creature's corpse to be immediately reduced to an innocuous puddle or pile of ashes. At the beginning of your next turn, even this remainder disappears and nothing is left of your target at all.

plus-circleGleaming Treasures: Somehow, the process of utter bodily annihilation leaves any useful loot the subject was carrying intact. You can still freely loot enemies defeated in this way, even if there's no body left to pat down.

plus-circleBattlefield Janitor: You may also dissolve the corpses of creatures you did not personally strike the killing blow on by targeting the corpse in question with any weapon attack.
Utility plus-circleDestroyer Of Stuff: As a procedure, you can carefully apply caustic material to inanimate objects of size 5 (approximately human-sized) or less in order to totally destroy them. You can destroy larger objects by doing this repeatedly, removing a man-sized chunk every time.

minus-circleLimited Hardness: You may only destroy objects whose overall toughness is approximately equal to wood/plastic or less (so no stone or metal).

minus-circleSupplies: Roll a trigger die when destroying an object in this way. If the result is 1-3, then doing so costs 1 Supplies. You cannot use this ability if you have no Supplies remaining.
caret-right Alternative plus-circleCrumbler: You can use Disposal to destroy inanimate objects made of stone or metal (or other materials of approximately equal toughness).

minus-circleHigher Concentration: Destroying an object made of stone/metal always costs 1 Supplies without any need to roll the trigger die.

minus-circleSlower Acting: Objects made of stone (or similar materials) require two procedures worth of time to fully dissolve instead of only one. Objects made of metal (or similar materials) require five procedures. You only need to be present and actively involved for the first procedure; the others will take care of themselves given time.

Insoluble

Protection plus-circleThem's My Molecules: You are completely immune to the Dissolving condition.
Protection plus-circleScoured Clean: Whenever you would normally gain the Dissolving condition if you weren't immune to it, roll a trigger die. If the result is 5+, you immediately remove/recover from any other single condition you are currently suffering from of your choice.

minus-circleSlow-Acting: You may attempt to remove another condition via the Insoluble ability a maximum of once per round, no matter how many times you are the subject of a Dissolving-causing effect.

Reintegration

Protection plus-circleDis-Disintegration: As those around you collapse into their constituent molecules, you salvage their losses to put yourself back together on the same level. Every time any creature within 10 meters of your position is harmed (loses 1 point from either a combat rating or Flesh) by the Dissolving condition, you immediately regain 1 point of lost Energy.

plus-circleAny Means Any: You gain the benefits of Reintegraton when ANY creature is damaged by the Dissolving condition within 10 meters of your position. This includes enemies, allies, and even yourself.

Ruination

Offense plus-circleSay Goodbye To Your Swag: Every time you would inflict the Dissolving condition to a subject that already has it (and thus would normally not do anything more of note) the subject immediately loses one Dosh or inventory item of their choice. Dosh or items lost in this way are permanently and irrevocably destroyed.

Slough

Offense plus-circleAcid Blood: Your bodily fluids are noticeably caustic. Every time you are damaged by a weapon attack, you may immediately inflict the Dissolving condition to any adjacent subject of your choice. The subject in question does not need to be your attacker, just anybody unlucky enough to be next to you.

minus-circleGotta Land: Attacks against you that fail or whose damage is reduced to 0 by your defenses do not count. You have to take at least 1 damage from an attack in order to spray acid with this ability.
Utility plus-circleCaustic Trail: You can choose for every space you pass through to be filled with corrosive puddles which last until the end of the current exploration turn. Any creature that passes through or ends their turn inside an affected space (including you) automatically gains the Dissolving condition.

plus-circleWide Trail: If you are larger than size 5 and thus occupy multiple spaces at once, you add caustic puddles to every space you pass through at once.

minus-circleSlow Pour: You take an impairment to movement when choosing to leave caustic puddles behind.

minus-circleFloor-Based: Creatures with the Aerialist ability from the Acrobat archetype are immune to this effect and essentially ignore your puddles entirely.