diff --git a/data/abilities.ts b/data/abilities.ts
index 2bbe4b3de8..a9080bd0c1 100644
--- a/data/abilities.ts
+++ b/data/abilities.ts
@@ -373,18 +373,20 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	beadsofruin: {
 		onStart(pokemon) {
-			if (this.suppressingAbility(pokemon)) return;
 			this.add('-ability', pokemon, 'Beads of Ruin');
+			this.field.addSourcedPseudoWeather('beadsofruin', pokemon, this.effect);
 		},
-		onAnyModifySpD(spd, target, source, move) {
-			const abilityHolder = this.effectState.target;
-			if (target.hasAbility('Beads of Ruin')) return;
-			if (!move.ruinedSpD?.hasAbility('Beads of Ruin')) move.ruinedSpD = abilityHolder;
-			if (move.ruinedSpD !== abilityHolder) return;
-			this.debug('Beads of Ruin SpD drop');
-			return this.chainModify(0.75);
+		onEnd(pokemon) {
+			this.field.removePseudoWeatherSource('beadsofruin', pokemon);
 		},
-		flags: {},
+		condition: {
+			onModifySpD(spd, target, source, move) {
+				if (this.field.pseudoWeather['beadsofruin'].activeSources.includes(target)) return;
+				this.debug('Beads of Ruin SpD drop');
+				return this.chainModify(0.75);
+			},
+		},
+		flags: { breakable: 1 },
 		name: "Beads of Ruin",
 		rating: 4.5,
 		num: 284,
@@ -2862,60 +2864,56 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 		onSwitchInPriority: 2,
 		onSwitchIn(pokemon) {
 			this.add('-ability', pokemon, 'Neutralizing Gas');
-			pokemon.abilityState.ending = false;
-			const strongWeathers = ['desolateland', 'primordialsea', 'deltastream'];
-			for (const target of this.getAllActive()) {
-				if (target.hasItem('Ability Shield')) {
-					this.add('-block', target, 'item: Ability Shield');
-					continue;
-				}
-				// Can't suppress a Tatsugiri inside of Dondozo already
-				if (target.volatiles['commanding']) {
-					continue;
-				}
-				if (target.illusion) {
-					this.singleEvent('End', this.dex.abilities.get('Illusion'), target.abilityState, target, pokemon, 'neutralizinggas');
-				}
-				if (target.volatiles['slowstart']) {
-					delete target.volatiles['slowstart'];
-					this.add('-end', target, 'Slow Start', '[silent]');
-				}
-				if (strongWeathers.includes(target.getAbility().id)) {
-					this.singleEvent('End', this.dex.abilities.get(target.getAbility().id), target.abilityState, target, pokemon, 'neutralizinggas');
-				}
-			}
+			this.field.addSourcedPseudoWeather('neutralizinggas', pokemon, this.effect);
 		},
-		onEnd(source) {
-			if (source.transformed) return;
-			for (const pokemon of this.getAllActive()) {
-				if (pokemon !== source && pokemon.hasAbility('Neutralizing Gas')) {
-					return;
-				}
+		onEnd(pokemon) {
+			if (!this.getAllActive().some(active => active !== pokemon && active.hasAbility('neutralizinggas'))) {
+				this.add('-end', pokemon, 'ability: Neutralizing Gas');
 			}
-			this.add('-end', source, 'ability: Neutralizing Gas');
 
 			// FIXME this happens before the pokemon switches out, should be the opposite order.
 			// Not an easy fix since we cant use a supported event. Would need some kind of special event that
 			// gathers events to run after the switch and then runs them when the ability is no longer accessible.
 			// (If you're tackling this, do note extreme weathers have the same issue)
 
-			// Mark this pokemon's ability as ending so Pokemon#ignoringAbility skips it
-			if (source.abilityState.ending) return;
-			source.abilityState.ending = true;
-			const sortedActive = this.getAllActive();
-			this.speedSort(sortedActive);
-			for (const pokemon of sortedActive) {
-				if (pokemon !== source) {
+			this.field.removePseudoWeatherSource('neutralizinggas', pokemon);
+		},
+		condition: {
+			onFieldStart() {
+				const strongWeathers = ['desolateland', 'primordialsea', 'deltastream'];
+				for (const target of this.getAllActive()) {
+					if (target.hasItem('Ability Shield')) {
+						this.add('-block', target, 'item: Ability Shield');
+						continue;
+					}
+					// Can't suppress a Tatsugiri inside of Dondozo already
+					if (target.volatiles['commanding']) continue;
+					if (target.illusion) {
+						this.singleEvent('End', this.dex.abilities.get('Illusion'), target.abilityState, target, null, 'neutralizinggas');
+					}
+					if (target.volatiles['slowstart']) {
+						delete target.volatiles['slowstart'];
+						this.add('-end', target, 'Slow Start', '[silent]');
+					}
+					if (strongWeathers.includes(target.getAbility().id)) {
+						this.singleEvent('End', this.dex.abilities.get(target.getAbility().id), target.abilityState, target, null, 'neutralizinggas');
+					}
+				}
+			},
+			onFieldEnd() {
+				const sortedActive = this.getAllActive();
+				this.speedSort(sortedActive);
+				for (const pokemon of sortedActive) {
 					if (pokemon.getAbility().flags['cantsuppress']) continue; // does not interact with e.g Ice Face, Zen Mode
 					if (pokemon.hasItem('abilityshield')) continue; // don't restart abilities that weren't suppressed
 
 					// Will be suppressed by Pokemon#ignoringAbility if needed
 					this.singleEvent('Start', pokemon.getAbility(), pokemon.abilityState, pokemon);
-					if (pokemon.ability === "gluttony") {
+					if (pokemon.ability === 'gluttony') {
 						pokemon.abilityState.gluttony = false;
 					}
 				}
-			}
+			},
 		},
 		flags: { failroleplay: 1, noreceiver: 1, noentrain: 1, notrace: 1, failskillswap: 1, notransform: 1 },
 		name: "Neutralizing Gas",
@@ -4775,18 +4773,20 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	swordofruin: {
 		onStart(pokemon) {
-			if (this.suppressingAbility(pokemon)) return;
 			this.add('-ability', pokemon, 'Sword of Ruin');
+			this.field.addSourcedPseudoWeather('swordofruin', pokemon, this.effect);
 		},
-		onAnyModifyDef(def, target, source, move) {
-			const abilityHolder = this.effectState.target;
-			if (target.hasAbility('Sword of Ruin')) return;
-			if (!move.ruinedDef?.hasAbility('Sword of Ruin')) move.ruinedDef = abilityHolder;
-			if (move.ruinedDef !== abilityHolder) return;
-			this.debug('Sword of Ruin Def drop');
-			return this.chainModify(0.75);
+		onEnd(pokemon) {
+			this.field.removePseudoWeatherSource('swordofruin', pokemon);
 		},
-		flags: {},
+		condition: {
+			onModifyDef(def, target, source, move) {
+				if (this.field.pseudoWeather['swordofruin'].activeSources.includes(target)) return;
+				this.debug('Sword of Ruin Def drop');
+				return this.chainModify(0.75);
+			},
+		},
+		flags: { breakable: 1 },
 		name: "Sword of Ruin",
 		rating: 4.5,
 		num: 285,
@@ -4828,18 +4828,20 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	tabletsofruin: {
 		onStart(pokemon) {
-			if (this.suppressingAbility(pokemon)) return;
 			this.add('-ability', pokemon, 'Tablets of Ruin');
+			this.field.addSourcedPseudoWeather('tabletsofruin', pokemon, this.effect);
 		},
-		onAnyModifyAtk(atk, source, target, move) {
-			const abilityHolder = this.effectState.target;
-			if (source.hasAbility('Tablets of Ruin')) return;
-			if (!move.ruinedAtk) move.ruinedAtk = abilityHolder;
-			if (move.ruinedAtk !== abilityHolder) return;
-			this.debug('Tablets of Ruin Atk drop');
-			return this.chainModify(0.75);
+		onEnd(pokemon) {
+			this.field.removePseudoWeatherSource('tabletsofruin', pokemon);
 		},
-		flags: {},
+		condition: {
+			onModifyAtk(atk, target, source, move) {
+				if (this.field.pseudoWeather['tabletsofruin'].activeSources.includes(target)) return;
+				this.debug('Tablets of Ruin Atk drop');
+				return this.chainModify(0.75);
+			},
+		},
+		flags: { breakable: 1 },
 		name: "Tablets of Ruin",
 		rating: 4.5,
 		num: 284,
@@ -5241,18 +5243,20 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	vesselofruin: {
 		onStart(pokemon) {
-			if (this.suppressingAbility(pokemon)) return;
 			this.add('-ability', pokemon, 'Vessel of Ruin');
+			this.field.addSourcedPseudoWeather('vesselofruin', pokemon, this.effect);
 		},
-		onAnyModifySpA(spa, source, target, move) {
-			const abilityHolder = this.effectState.target;
-			if (source.hasAbility('Vessel of Ruin')) return;
-			if (!move.ruinedSpA) move.ruinedSpA = abilityHolder;
-			if (move.ruinedSpA !== abilityHolder) return;
-			this.debug('Vessel of Ruin SpA drop');
-			return this.chainModify(0.75);
+		onEnd(pokemon) {
+			this.field.removePseudoWeatherSource('vesselofruin', pokemon);
 		},
-		flags: {},
+		condition: {
+			onModifySpA(spa, target, source, move) {
+				if (this.field.pseudoWeather['vesselofruin'].activeSources.includes(target)) return;
+				this.debug('Vessel of Ruin SpA drop');
+				return this.chainModify(0.75);
+			},
+		},
+		flags: { breakable: 1 },
 		name: "Vessel of Ruin",
 		rating: 4.5,
 		num: 284,
diff --git a/data/mods/gen9ssb/abilities.ts b/data/mods/gen9ssb/abilities.ts
index 10afe20079..245302a4c2 100644
--- a/data/mods/gen9ssb/abilities.ts
+++ b/data/mods/gen9ssb/abilities.ts
@@ -230,22 +230,23 @@ export const Abilities: import('../../../sim/dex-abilities').ModdedAbilityDataTa
 		desc: "Active Pokemon without this Ability have their Defense multiplied by 0.85x. This Pokemon's moves and their effects ignore certain Abilities of other Pokemon.",
 		name: "Quag of Ruin",
 		onStart(pokemon) {
-			if (this.suppressingAbility(pokemon)) return;
 			this.add('-ability', pokemon, 'Quag of Ruin');
+			this.field.addSourcedPseudoWeather('quagofruin', pokemon, this.effect);
 		},
-		onAnyModifyDef(def, target, source, move) {
-			if (!move) return;
-			const abilityHolder = this.effectState.target;
-			if (target.hasAbility('Quag of Ruin')) return;
-			if (!move.ruinedDef?.hasAbility('Quag of Ruin')) move.ruinedDef = abilityHolder;
-			if (move.ruinedDef !== abilityHolder) return;
-			this.debug('Quag of Ruin Def drop');
-			return this.chainModify(0.85);
+		onEnd(pokemon) {
+			this.field.removePseudoWeatherSource('quagofruin', pokemon);
+		},
+		condition: {
+			onModifyDef(def, target, source, move) {
+				if (this.field.pseudoWeather['quagofruin'].activeSources.includes(target)) return;
+				this.debug('Quag of Ruin Def drop');
+				return this.chainModify(0.85);
+			},
 		},
 		onModifyMove(move) {
 			move.ignoreAbility = true;
 		},
-		flags: {},
+		flags: { breakable: 1 },
 		gen: 9,
 	},
 	clodofruin: {
@@ -254,15 +255,17 @@ export const Abilities: import('../../../sim/dex-abilities').ModdedAbilityDataTa
 		name: "Clod of Ruin",
 		onStart(pokemon) {
 			this.add('-ability', pokemon, 'Clod of Ruin');
+			this.field.addSourcedPseudoWeather('clodofruin', pokemon, this.effect);
 		},
-		onAnyModifyAtk(atk, target, source, move) {
-			if (!move) return;
-			const abilityHolder = this.effectState.target;
-			if (target.hasAbility('Clod of Ruin')) return;
-			if (!move.ruinedAtk?.hasAbility('Clod of Ruin')) move.ruinedAtk = abilityHolder;
-			if (move.ruinedAtk !== abilityHolder) return;
-			this.debug('Clod of Ruin Atk drop');
-			return this.chainModify(0.85);
+		onEnd(pokemon) {
+			this.field.removePseudoWeatherSource('clodofruin', pokemon);
+		},
+		condition: {
+			onModifyAtk(atk, target, source, move) {
+				if (this.field.pseudoWeather['clodofruin'].activeSources.includes(target)) return;
+				this.debug('Clod of Ruin Atk drop');
+				return this.chainModify(0.85);
+			},
 		},
 		onAnyModifyBoost(boosts, pokemon) {
 			const unawareUser = this.effectState.target;
@@ -474,11 +477,17 @@ export const Abilities: import('../../../sim/dex-abilities').ModdedAbilityDataTa
 		onStart(pokemon) {
 			this.add('-ability', pokemon, 'Blitz of Ruin');
 			this.add('-message', `${pokemon.name}'s Blitz of Ruin lowered the Speed of all surrounding Pokémon!`);
+			this.field.addSourcedPseudoWeather('blitzofruin', pokemon, this.effect);
 		},
-		onAnyModifySpe(spe, pokemon) {
-			if (!pokemon.hasAbility('Blitz of Ruin')) {
+		onEnd(pokemon) {
+			this.field.removePseudoWeatherSource('blitzofruin', pokemon);
+		},
+		condition: {
+			onModifySpe(spe, target) {
+				if (this.field.pseudoWeather['blitzofruin'].activeSources.includes(target)) return;
+				this.debug('Blitz of Ruin Spe drop');
 				return this.chainModify(0.75);
-			}
+			},
 		},
 		flags: { breakable: 1 },
 	},
diff --git a/sim/battle-actions.ts b/sim/battle-actions.ts
index 66fd617e6d..d76ae18fd5 100644
--- a/sim/battle-actions.ts
+++ b/sim/battle-actions.ts
@@ -101,6 +101,7 @@ export class BattleActions {
 			// will definitely switch out at this point
 
 			this.battle.singleEvent('End', oldActive.getAbility(), oldActive.abilityState, oldActive);
+			this.battle.field.removeSourceFromPseudoWeather(oldActive);
 			this.battle.singleEvent('End', oldActive.getItem(), oldActive.itemState, oldActive);
 
 			// if a pokemon is forced out by Whirlwind/etc or Eject Button/Pack, it can't use its chosen move
diff --git a/sim/battle.ts b/sim/battle.ts
index 7a4d67aa65..7888836c7d 100644
--- a/sim/battle.ts
+++ b/sim/battle.ts
@@ -599,16 +599,16 @@ export class Battle {
 			// it's changed; call it off
 			return relayVar;
 		}
-		if (eventid === 'SwitchIn' && effect.effectType === 'Ability' && effect.flags['breakable'] &&
-			this.suppressingAbility(target as Pokemon)) {
-			this.debug(eventid + ' handler suppressed by Mold Breaker');
-			return relayVar;
-		}
 		if (eventid !== 'Start' && eventid !== 'TakeItem' && eventid !== 'SetAbility' && effect.effectType === 'Item' &&
 			(target instanceof Pokemon) && target.ignoringItem()) {
 			this.debug(eventid + ' handler suppressed by Embargo, Klutz or Magic Room');
 			return relayVar;
 		}
+		if ((['SwitchIn', 'Start', 'End', 'SwitchOut']).includes(eventid) && effect.effectType === 'Ability' &&
+			effect.flags['breakable'] && this.suppressingAbility(target as Pokemon)) {
+			this.debug(eventid + ' handler suppressed by Mold Breaker');
+			return relayVar;
+		}
 		if (eventid !== 'End' && effect.effectType === 'Ability' && (target instanceof Pokemon) && target.ignoringAbility()) {
 			this.debug(eventid + ' handler suppressed by Gastro Acid or Neutralizing Gas');
 			return relayVar;
diff --git a/sim/dex-moves.ts b/sim/dex-moves.ts
index f159dc1155..629d6f6ef5 100644
--- a/sim/dex-moves.ts
+++ b/sim/dex-moves.ts
@@ -339,10 +339,6 @@ export interface ActiveMove extends MutableMove {
 	totalDamage?: number | false;
 	typeChangerBoosted?: Effect;
 	infiltrates?: boolean;
-	ruinedAtk?: Pokemon;
-	ruinedDef?: Pokemon;
-	ruinedSpA?: Pokemon;
-	ruinedSpD?: Pokemon;
 
 	/**
 	 * Has this move been boosted by a Z-crystal or used by a Dynamax Pokemon? Usually the same as
diff --git a/sim/field.ts b/sim/field.ts
index eb01c17b15..9e69dc05fc 100644
--- a/sim/field.ts
+++ b/sim/field.ts
@@ -229,6 +229,51 @@ export class Field {
 		return true;
 	}
 
+	/**
+	 * Start a field effect if it is not already active and maintain a list of sources.
+	 * The field effect is only removed when all sources deactivate it.
+	 */
+	addSourcedPseudoWeather(
+		status: string | Condition,
+		source: Pokemon,
+		sourceEffect: Effect | null = null
+	): boolean {
+		const returnValue = this.addPseudoWeather(status, source, sourceEffect);
+		status = this.battle.dex.conditions.get(status);
+		const state = this.pseudoWeather[status.id];
+		if (state) {
+			if (!state.activeSources) state.activeSources = [];
+			state.activeSources.push(source);
+		}
+		return returnValue;
+	}
+
+	/**
+	 * Remove a source from a field effect. If no sources remain, the effect is removed.
+	 */
+	removePseudoWeatherSource(status: string | Effect, source: Pokemon) {
+		status = this.battle.dex.conditions.get(status);
+		const state = this.pseudoWeather[status.id];
+		if (!state) return false;
+		if (!state.activeSources) throw new Error(`removing pseudoweather without a source`);
+		state.activeSources = state.activeSources.filter((s: Pokemon) => s !== source);
+		if (state.activeSources.length) return false;
+		delete this.pseudoWeather[status.id];
+		this.battle.singleEvent('FieldEnd', status, state, this);
+		return true;
+	}
+
+	/**
+	 * Remove a source from all active field effects. Used when a Pokemon leaves the field.
+	 */
+	removeSourceFromPseudoWeather(source: Pokemon) {
+		for (const id in this.pseudoWeather) {
+			if (this.pseudoWeather[id].activeSources) {
+				this.removePseudoWeatherSource(id, source);
+			}
+		}
+	}
+
 	destroy() {
 		// deallocate ourself
 
diff --git a/sim/pokemon.ts b/sim/pokemon.ts
index b9283feb3a..8df038f264 100644
--- a/sim/pokemon.ts
+++ b/sim/pokemon.ts
@@ -870,15 +870,9 @@ export class Pokemon {
 		if (this.getAbility().flags['cantsuppress']) return false;
 		if (this.volatiles['gastroacid']) return true;
 
-		// Check if any active pokemon have the ability Neutralizing Gas
 		if (this.hasItem('Ability Shield') || this.ability === ('neutralizinggas' as ID)) return false;
-		for (const pokemon of this.battle.getAllActive()) {
-			// can't use hasAbility because it would lead to infinite recursion
-			if (pokemon.ability === ('neutralizinggas' as ID) && !pokemon.volatiles['gastroacid'] &&
-				!pokemon.transformed && !pokemon.abilityState.ending && !this.volatiles['commanding']) {
-				return true;
-			}
-		}
+		if (this.volatiles['commanding']) return false;
+		if (this.battle.field.getPseudoWeather('neutralizinggas')) return true;
 
 		return false;
 	}
diff --git a/test/sim/abilities/swordofruin.js b/test/sim/abilities/swordofruin.js
index c795977796..5b8e19ae38 100644
--- a/test/sim/abilities/swordofruin.js
+++ b/test/sim/abilities/swordofruin.js
@@ -23,7 +23,7 @@ describe(`Sword of Ruin`, () => {
 	});
 
 	it(`should not lower the Defense of other Pokemon with the Sword of Ruin Ability`, () => {
-		battle = common.createBattle({ forceRandomChance: false }, [[
+		battle = common.createBattle([[
 			{ species: 'wynaut', ability: 'swordofruin', moves: ['sleeptalk'] },
 		], [
 			{ species: 'chienpao', ability: 'swordofruin', moves: ['aerialace'] },
@@ -33,4 +33,78 @@ describe(`Sword of Ruin`, () => {
 		const damage = wynaut.maxhp - wynaut.hp;
 		assert.bounded(damage, [90, 107]);
 	});
+
+	it(`effect should end if its ability is changed`, () => {
+		battle = common.createBattle([[
+			{ species: 'wynaut', ability: 'shellarmor', moves: ['worryseed'] },
+		], [
+			{ species: 'chienpao', ability: 'swordofruin', moves: ['aerialace'] },
+		]]);
+		battle.makeChoices();
+		const wynaut = battle.p1.active[0];
+		const hp = wynaut.hp;
+		let damage = wynaut.maxhp - hp;
+		assert.bounded(damage, [120, 142]);
+
+		battle.makeChoices();
+		damage = hp - wynaut.hp;
+		assert.bounded(damage, [90, 107]);
+	});
+
+	it(`effect should not end if its ability is changed by a Mold Breaker move, but should end after switching out`, () => {
+		battle = common.createBattle([[
+			{ species: 'wynaut', ability: 'moldbreaker', moves: ['worryseed', 'recover'] },
+		], [
+			{ species: 'chienpao', ability: 'swordofruin', moves: ['aerialace'] },
+			{ species: 'weavile', moves: ['aerialace'] },
+		]]);
+		battle.makeChoices();
+		const wynaut = battle.p1.active[0];
+		let damage = wynaut.maxhp - wynaut.hp;
+		assert.bounded(damage, [120, 142]);
+
+		let hp = wynaut.hp;
+		battle.makeChoices();
+		damage = hp - wynaut.hp;
+		assert.bounded(damage, [120, 142]);
+
+		battle.makeChoices('move recover', 'switch weavile');
+
+		hp = wynaut.hp;
+		battle.makeChoices();
+		damage = hp - wynaut.hp;
+		assert.bounded(damage, [90, 107]);
+	});
+
+	it(`should not lower the Defense of other Pokemon that lost its ability to a Mold Breaker move`, () => {
+		battle = common.createBattle([[
+			{ species: 'wynaut', ability: 'swordofruin', moves: ['sleeptalk'] },
+		], [
+			{ species: 'magikarp', ability: 'moldbreaker', moves: ['worryseed'] },
+			{ species: 'chienpao', ability: 'swordofruin', moves: ['aerialace'] },
+		]]);
+		battle.makeChoices();
+		battle.makeChoices('auto', 'switch 2');
+		battle.makeChoices();
+		const wynaut = battle.p1.active[0];
+		const damage = wynaut.maxhp - wynaut.hp;
+		assert.bounded(damage, [90, 107]);
+	});
+
+	it(`should lower the Defense of other Pokemon dragged in by a Mold Breaker move`, () => {
+		battle = common.createBattle([[
+			{ species: 'wynaut', ability: 'moldbreaker', moves: ['roar'] },
+			{ species: 'chienpao', ability: 'swordofruin', moves: ['aerialace'] },
+		], [
+			{ species: 'wynaut', moves: ['sleeptalk'] },
+			{ species: 'chienpao', ability: 'swordofruin', moves: ['aerialace', 'sleeptalk'] },
+		]]);
+		battle.makeChoices();
+		battle.makeChoices('switch 2', 'move sleeptalk');
+		const regularPao = battle.p1.active[0];
+		const moldedPao = battle.p2.active[0];
+		battle.makeChoices();
+		assert.bounded(regularPao.maxhp - regularPao.hp, [61, 72]);
+		assert.bounded(moldedPao.maxhp - moldedPao.hp, [81, 96]);
+	});
 });