diff --git a/src/modifier/modifier-type.ts b/src/modifier/modifier-type.ts
index 942ef4e1bfc..16a74757598 100644
--- a/src/modifier/modifier-type.ts
+++ b/src/modifier/modifier-type.ts
@@ -115,6 +115,26 @@ export class ModifierType {
     return this;
   }
 
+  /**
+   * Populates the tier field by performing a reverse lookup on the modifier pool specified by {@linkcode poolType} using the
+   * {@linkcode ModifierType}'s id.
+   * @param poolType the {@linkcode ModifierPoolType} to look into to derive the item's tier; defaults to {@linkcode ModifierPoolType.PLAYER}
+   */
+  withTierFromPool(poolType: ModifierPoolType = ModifierPoolType.PLAYER): ModifierType {
+    for (const tier of Object.values(getModifierPoolForType(poolType))) {
+      for (const modifier of tier) {
+        if (this.id === modifier.modifierType.id) {
+          this.tier = modifier.modifierType.tier;
+          break;
+        }
+      }
+      if (this.tier) {
+        break;
+      }
+    }
+    return this;
+  }
+
   newModifier(...args: any[]): Modifier | null {
     return this.newModifierFunc && this.newModifierFunc(this, args);
   }
@@ -855,7 +875,7 @@ export class FusePokemonModifierType extends PokemonModifierType {
 class AttackTypeBoosterModifierTypeGenerator extends ModifierTypeGenerator {
   constructor() {
     super((party: Pokemon[], pregenArgs?: any[]) => {
-      if (pregenArgs) {
+      if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in Type)) {
         return new AttackTypeBoosterModifierType(pregenArgs[0] as Type, 20);
       }
 
@@ -919,12 +939,13 @@ class SpeciesStatBoosterModifierTypeGenerator extends ModifierTypeGenerator {
 
   constructor() {
     super((party: Pokemon[], pregenArgs?: any[]) => {
-      if (pregenArgs) {
+      const items = SpeciesStatBoosterModifierTypeGenerator.items;
+      if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in items)) {
         return new SpeciesStatBoosterModifierType(pregenArgs[0] as SpeciesStatBoosterItem);
       }
 
-      const values = Object.values(SpeciesStatBoosterModifierTypeGenerator.items);
-      const keys = Object.keys(SpeciesStatBoosterModifierTypeGenerator.items);
+      const values = Object.values(items);
+      const keys = Object.keys(items);
       const weights = keys.map(() => 0);
 
       for (const p of party) {
@@ -979,7 +1000,10 @@ class SpeciesStatBoosterModifierTypeGenerator extends ModifierTypeGenerator {
 
 class TmModifierTypeGenerator extends ModifierTypeGenerator {
   constructor(tier: ModifierTier) {
-    super((party: Pokemon[]) => {
+    super((party: Pokemon[], pregenArgs?: any[]) => {
+      if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in Moves)) {
+        return new TmModifierType(pregenArgs[0] as Moves);
+      }
       const partyMemberCompatibleTms = party.map(p => (p as PlayerPokemon).compatibleTms.filter(tm => !p.moveset.find(m => m?.moveId === tm)));
       const tierUniqueCompatibleTms = partyMemberCompatibleTms.flat().filter(tm => tmPoolTiers[tm] === tier).filter(tm => !allMoves[tm].name.endsWith(" (N)")).filter((tm, i, array) => array.indexOf(tm) === i);
       if (!tierUniqueCompatibleTms.length) {
@@ -994,7 +1018,7 @@ class TmModifierTypeGenerator extends ModifierTypeGenerator {
 class EvolutionItemModifierTypeGenerator extends ModifierTypeGenerator {
   constructor(rare: boolean) {
     super((party: Pokemon[], pregenArgs?: any[]) => {
-      if (pregenArgs) {
+      if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in EvolutionItem)) {
         return new EvolutionItemModifierType(pregenArgs[0] as EvolutionItem);
       }
 
@@ -1021,7 +1045,7 @@ class EvolutionItemModifierTypeGenerator extends ModifierTypeGenerator {
 class FormChangeItemModifierTypeGenerator extends ModifierTypeGenerator {
   constructor() {
     super((party: Pokemon[], pregenArgs?: any[]) => {
-      if (pregenArgs) {
+      if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in FormChangeItem)) {
         return new FormChangeItemModifierType(pregenArgs[0] as FormChangeItem);
       }
 
@@ -1274,7 +1298,7 @@ export const modifierTypes = {
   SPECIES_STAT_BOOSTER: () => new SpeciesStatBoosterModifierTypeGenerator(),
 
   TEMP_STAT_BOOSTER: () => new ModifierTypeGenerator((party: Pokemon[], pregenArgs?: any[]) => {
-    if (pregenArgs) {
+    if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in TempBattleStat)) {
       return new TempBattleStatBoosterModifierType(pregenArgs[0] as TempBattleStat);
     }
     const randTempBattleStat = Utils.randSeedInt(6) as TempBattleStat;
@@ -1283,7 +1307,7 @@ export const modifierTypes = {
   DIRE_HIT: () => new TempBattleStatBoosterModifierType(TempBattleStat.CRIT),
 
   BASE_STAT_BOOSTER: () => new ModifierTypeGenerator((party: Pokemon[], pregenArgs?: any[]) => {
-    if (pregenArgs) {
+    if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in Stat)) {
       const stat = pregenArgs[0] as Stat;
       return new PokemonBaseStatBoosterModifierType(getBaseStatBoosterItemName(stat), stat);
     }
@@ -1294,14 +1318,14 @@ export const modifierTypes = {
   ATTACK_TYPE_BOOSTER: () => new AttackTypeBoosterModifierTypeGenerator(),
 
   MINT: () => new ModifierTypeGenerator((party: Pokemon[], pregenArgs?: any[]) => {
-    if (pregenArgs) {
+    if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in Nature)) {
       return new PokemonNatureChangeModifierType(pregenArgs[0] as Nature);
     }
     return new PokemonNatureChangeModifierType(Utils.randSeedInt(Utils.getEnumValues(Nature).length) as Nature);
   }),
 
   TERA_SHARD: () => new ModifierTypeGenerator((party: Pokemon[], pregenArgs?: any[]) => {
-    if (pregenArgs) {
+    if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in Type)) {
       return new TerastallizeModifierType(pregenArgs[0] as Type);
     }
     if (!party[0].scene.getModifiers(Modifiers.TerastallizeAccessModifier).length) {
@@ -1318,7 +1342,7 @@ export const modifierTypes = {
   }),
 
   BERRY: () => new ModifierTypeGenerator((party: Pokemon[], pregenArgs?: any[]) => {
-    if (pregenArgs) {
+    if (pregenArgs && (pregenArgs.length === 1) && (pregenArgs[0] in BerryType)) {
       return new BerryModifierType(pregenArgs[0] as BerryType);
     }
     const berryTypes = Utils.getEnumValues(BerryType);
@@ -1908,15 +1932,36 @@ export function getPlayerModifierTypeOptions(count: integer, party: PlayerPokemo
     }
   });
 
-  // OVERRIDE IF NECESSARY
-  Overrides.ITEM_REWARD_OVERRIDE.forEach((item, i) => {
-    const override = modifierTypes[item]();
-    options[i].type = override instanceof ModifierTypeGenerator ? override.generateType(party) : override;
-  });
+  overridePlayerModifierTypeOptions(options, party);
 
   return options;
 }
 
+/**
+ * Replaces the {@linkcode ModifierType} of the entries within {@linkcode options} with any
+ * {@linkcode ModifierOverride} entries listed in {@linkcode Overrides.ITEM_REWARD_OVERRIDE}
+ * up to the smallest amount of entries between {@linkcode options} and the override array.
+ * @param options Array of naturally rolled {@linkcode ModifierTypeOption}s
+ * @param party Array of the player's current party
+ */
+export function overridePlayerModifierTypeOptions(options: ModifierTypeOption[], party: PlayerPokemon[]) {
+  const minLength = Math.min(options.length, Overrides.ITEM_REWARD_OVERRIDE.length);
+  for (let i = 0; i < minLength; i++) {
+    const override: ModifierOverride = Overrides.ITEM_REWARD_OVERRIDE[i];
+    const modifierFunc = modifierTypes[override.name];
+    let modifierType: ModifierType | null = modifierFunc();
+
+    if (modifierType instanceof ModifierTypeGenerator) {
+      const pregenArgs = ("type" in override) && (override.type !== null) ? [override.type] : undefined;
+      modifierType = modifierType.generateType(party, pregenArgs);
+    }
+
+    if (modifierType) {
+      options[i].type = modifierType.withIdFromFunc(modifierFunc).withTierFromPool();
+    }
+  }
+}
+
 export function getPlayerShopModifierTypeOptionsForWave(waveIndex: integer, baseCost: integer): ModifierTypeOption[] {
   if (!(waveIndex % 10)) {
     return [];
@@ -1955,7 +2000,19 @@ export function getPlayerShopModifierTypeOptionsForWave(waveIndex: integer, base
 }
 
 export function getEnemyBuffModifierForWave(tier: ModifierTier, enemyModifiers: Modifiers.PersistentModifier[], scene: BattleScene): Modifiers.EnemyPersistentModifier {
-  const tierStackCount = tier === ModifierTier.ULTRA ? 5 : tier === ModifierTier.GREAT ? 3 : 1;
+  let tierStackCount: number;
+  switch (tier) {
+  case ModifierTier.ULTRA:
+    tierStackCount = 5;
+    break;
+  case ModifierTier.GREAT:
+    tierStackCount = 3;
+    break;
+  default:
+    tierStackCount = 1;
+    break;
+  }
+
   const retryCount = 50;
   let candidate = getNewModifierTypeOption([], ModifierPoolType.ENEMY_BUFF, tier);
   let r = 0;
@@ -1983,7 +2040,20 @@ export function getDailyRunStarterModifiers(party: PlayerPokemon[]): Modifiers.P
   for (const p of party) {
     for (let m = 0; m < 3; m++) {
       const tierValue = Utils.randSeedInt(64);
-      const tier = tierValue > 25 ? ModifierTier.COMMON : tierValue > 12 ? ModifierTier.GREAT : tierValue > 4 ? ModifierTier.ULTRA : tierValue ? ModifierTier.ROGUE : ModifierTier.MASTER;
+
+      let tier: ModifierTier;
+      if (tierValue > 25) {
+        tier = ModifierTier.COMMON;
+      } else if (tierValue > 12) {
+        tier = ModifierTier.GREAT;
+      } else if (tierValue > 4) {
+        tier = ModifierTier.ULTRA;
+      } else if (tierValue) {
+        tier = ModifierTier.ROGUE;
+      } else {
+        tier = ModifierTier.MASTER;
+      }
+
       const modifier = getNewModifierTypeOption(party, ModifierPoolType.DAILY_STARTER, tier)?.type?.newModifier(p) as Modifiers.PokemonHeldItemModifier;
       ret.push(modifier);
     }
@@ -2029,7 +2099,19 @@ function getNewModifierTypeOption(party: Pokemon[], poolType: ModifierPoolType,
         }
       } while (upgraded);
     }
-    tier = tierValue > 255 ? ModifierTier.COMMON : tierValue > 60 ? ModifierTier.GREAT : tierValue > 12 ? ModifierTier.ULTRA : tierValue ? ModifierTier.ROGUE : ModifierTier.MASTER;
+
+    if (tierValue > 255) {
+      tier = ModifierTier.COMMON;
+    } else if (tierValue > 60) {
+      tier = ModifierTier.GREAT;
+    } else if (tierValue > 12) {
+      tier = ModifierTier.ULTRA;
+    } else if (tierValue) {
+      tier = ModifierTier.ROGUE;
+    } else {
+      tier = ModifierTier.MASTER;
+    }
+
     tier += upgradeCount;
     while (tier && (!modifierPool.hasOwnProperty(tier) || !modifierPool[tier].length)) {
       tier--;
@@ -2122,6 +2204,19 @@ export function getLuckString(luckValue: integer): string {
 }
 
 export function getLuckTextTint(luckValue: integer): integer {
-  const modifierTier = luckValue ? luckValue > 2 ? luckValue > 5 ? luckValue > 9 ? luckValue > 11 ? ModifierTier.LUXURY : ModifierTier.MASTER : ModifierTier.ROGUE : ModifierTier.ULTRA : ModifierTier.GREAT : ModifierTier.COMMON;
+  let modifierTier: ModifierTier;
+  if (luckValue > 11) {
+    modifierTier = ModifierTier.LUXURY;
+  } else if (luckValue > 9) {
+    modifierTier = ModifierTier.MASTER;
+  } else if (luckValue > 5) {
+    modifierTier = ModifierTier.ROGUE;
+  } else if (luckValue > 2) {
+    modifierTier = ModifierTier.ULTRA;
+  } else if (luckValue) {
+    modifierTier = ModifierTier.GREAT;
+  } else {
+    modifierTier = ModifierTier.COMMON;
+  }
   return getModifierTierTextTint(modifierTier);
 }
diff --git a/src/modifier/modifier.ts b/src/modifier/modifier.ts
index c6871353a7d..93ea067e424 100644
--- a/src/modifier/modifier.ts
+++ b/src/modifier/modifier.ts
@@ -2734,30 +2734,29 @@ export class EnemyFusionChanceModifier extends EnemyPersistentModifier {
 }
 
 /**
- * Uses override from overrides.ts to set PersistentModifiers for starting a new game
- * @param scene current BattleScene
- * @param player is this for player for enemy
+ * Uses either `MODIFIER_OVERRIDE` in overrides.ts to set {@linkcode PersistentModifier}s for either:
+ *  - The player
+ *  - The enemy
+ * @param scene current {@linkcode BattleScene}
+ * @param isPlayer {@linkcode boolean} for whether the the player (`true`) or enemy (`false`) is being overridden
  */
-export function overrideModifiers(scene: BattleScene, player: boolean = true): void {
-  const modifierOverride = player ? Overrides.STARTING_MODIFIER_OVERRIDE : Overrides.OPP_MODIFIER_OVERRIDE;
-  if (!modifierOverride || modifierOverride.length === 0 || !scene) {
+export function overrideModifiers(scene: BattleScene, isPlayer: boolean = true): void {
+  const modifiersOverride: ModifierTypes.ModifierOverride[] = isPlayer ? Overrides.STARTING_MODIFIER_OVERRIDE : Overrides.OPP_MODIFIER_OVERRIDE;
+  if (!modifiersOverride || modifiersOverride.length === 0 || !scene) {
     return;
-  } // if no override, do nothing
-  // if it's the opponent, we clear all his current modifiers to avoid stacking
-  if (!player) {
+  }
+
+  // If it's the opponent, clear all of their current modifiers to avoid stacking
+  if (!isPlayer) {
     scene.clearEnemyModifiers();
   }
-  // we loop through all the modifier name given in the override file
-  modifierOverride.forEach(item => {
-    const modifierName = item.name;
-    const qty = item.count || 1;
-    if (!modifierTypes.hasOwnProperty(modifierName)) {
-      return;
-    } // if the modifier does not exist, we skip it
-    const modifierType: ModifierType = modifierTypes[modifierName]();
-    const modifier: PersistentModifier = modifierType.withIdFromFunc(modifierTypes[modifierName]).newModifier() as PersistentModifier;
-    modifier.stackCount = qty;
-    if (player) {
+
+  modifiersOverride.forEach(item => {
+    const modifierFunc = modifierTypes[item.name];
+    const modifier = modifierFunc().withIdFromFunc(modifierFunc).newModifier() as PersistentModifier;
+    modifier.stackCount = item.count || 1;
+
+    if (isPlayer) {
       scene.addModifier(modifier, true, false, false, true);
     } else {
       scene.addEnemyModifier(modifier, true, true);
@@ -2766,37 +2765,38 @@ export function overrideModifiers(scene: BattleScene, player: boolean = true): v
 }
 
 /**
- * Uses override from overrides.ts to set PokemonHeldItemModifiers for starting a new game
- * @param scene current BattleScene
- * @param player is this for player for enemy
+ * Uses either `HELD_ITEMS_OVERRIDE` in overrides.ts to set {@linkcode PokemonHeldItemModifier}s for either:
+ *  - The first member of the player's team when starting a new game
+ *  - An enemy {@linkcode Pokemon} being spawned in
+ * @param scene current {@linkcode BattleScene}
+ * @param pokemon {@linkcode Pokemon} whose held items are being overridden
+ * @param isPlayer {@linkcode boolean} for whether the {@linkcode pokemon} is the player's (`true`) or an enemy (`false`)
  */
-export function overrideHeldItems(scene: BattleScene, pokemon: Pokemon, player: boolean = true): void {
-  const heldItemsOverride = player ? Overrides.STARTING_HELD_ITEMS_OVERRIDE : Overrides.OPP_HELD_ITEMS_OVERRIDE;
+export function overrideHeldItems(scene: BattleScene, pokemon: Pokemon, isPlayer: boolean = true): void {
+  const heldItemsOverride: ModifierTypes.ModifierOverride[] = isPlayer ? Overrides.STARTING_HELD_ITEMS_OVERRIDE : Overrides.OPP_HELD_ITEMS_OVERRIDE;
   if (!heldItemsOverride || heldItemsOverride.length === 0 || !scene) {
     return;
-  } // if no override, do nothing
-  // we loop through all the itemName given in the override file
+  }
+
   heldItemsOverride.forEach(item => {
-    const itemName = item.name;
+    const modifierFunc = modifierTypes[item.name];
+    let modifierType: ModifierType | null = modifierFunc();
     const qty = item.count || 1;
-    if (!modifierTypes.hasOwnProperty(itemName)) {
-      return;
-    } // if the item does not exist, we skip it
-    const modifierType: ModifierType = modifierTypes[itemName](); // we retrieve the item in the list
-    let itemModifier: PokemonHeldItemModifier;
+
     if (modifierType instanceof ModifierTypes.ModifierTypeGenerator) {
-      const pregenArgs = "type" in item ? [item.type] : undefined;
-      itemModifier = modifierType.generateType([], pregenArgs)?.withIdFromFunc(modifierTypes[itemName]).newModifier(pokemon) as PokemonHeldItemModifier;
-    } else {
-      itemModifier = modifierType.withIdFromFunc(modifierTypes[itemName]).newModifier(pokemon) as PokemonHeldItemModifier;
+      const pregenArgs = ("type" in item) && (item.type !== null) ? [item.type] : undefined;
+      modifierType = modifierType.generateType([], pregenArgs);
     }
-    // we create the item
-    itemModifier.pokemonId = pokemon.id; // we assign the created item to the pokemon
-    itemModifier.stackCount = qty; // we say how many items we want
-    if (player) {
-      scene.addModifier(itemModifier, true, false, false, true);
-    } else {
-      scene.addEnemyModifier(itemModifier, true, true);
+
+    const heldItemModifier = modifierType && modifierType.withIdFromFunc(modifierFunc).newModifier(pokemon) as PokemonHeldItemModifier;
+    if (heldItemModifier) {
+      heldItemModifier.pokemonId = pokemon.id;
+      heldItemModifier.stackCount = qty;
+      if (isPlayer) {
+        scene.addModifier(heldItemModifier, true, false, false, true);
+      } else {
+        scene.addEnemyModifier(heldItemModifier, true, true);
+      }
     }
   });
 }
diff --git a/src/overrides.ts b/src/overrides.ts
index 88db105475c..8b3d628e05e 100644
--- a/src/overrides.ts
+++ b/src/overrides.ts
@@ -12,7 +12,7 @@ import { type PokeballCounts } from "./battle-scene";
 import { Gender } from "./data/gender";
 import { allSpecies } from "./data/pokemon-species"; // eslint-disable-line @typescript-eslint/no-unused-vars
 import { Variant } from "./data/variant";
-import { type ModifierOverride, type ModifierTypeKeys } from "./modifier/modifier-type";
+import { type ModifierOverride } from "./modifier/modifier-type";
 
 /**
  * Overrides that are using when testing different in game situations
@@ -51,6 +51,7 @@ class DefaultOverrides {
   readonly ARENA_TINT_OVERRIDE: TimeOfDay | null = null;
   /** Multiplies XP gained by this value including 0. Set to null to ignore the override */
   readonly XP_MULTIPLIER_OVERRIDE: number | null = null;
+  readonly NEVER_CRIT_OVERRIDE: boolean = false;
   /** default 1000 */
   readonly STARTING_MONEY_OVERRIDE: integer = 0;
   /** Sets all shop item prices to 0 */
@@ -155,20 +156,28 @@ class DefaultOverrides {
    * STARTING_HELD_ITEM_OVERRIDE = [{name: "BERRY"}]
    * ```
    */
-  readonly STARTING_MODIFIER_OVERRIDE: Array<ModifierOverride> = [];
-  readonly OPP_MODIFIER_OVERRIDE: Array<ModifierOverride> = [];
+  readonly STARTING_MODIFIER_OVERRIDE: ModifierOverride[] = [];
+  /**
+   * Override array of {@linkcode ModifierOverride}s used to provide modifiers to enemies.
+   *
+   * Note that any previous modifiers are cleared.
+   */
+  readonly OPP_MODIFIER_OVERRIDE: ModifierOverride[] = [];
 
-  readonly STARTING_HELD_ITEMS_OVERRIDE: Array<ModifierOverride> = [];
-  readonly OPP_HELD_ITEMS_OVERRIDE: Array<ModifierOverride> = [];
-  readonly NEVER_CRIT_OVERRIDE: boolean = false;
+  /** Override array of {@linkcode ModifierOverride}s used to provide held items to first party member when starting a new game. */
+  readonly STARTING_HELD_ITEMS_OVERRIDE: ModifierOverride[] = [];
+  /** Override array of {@linkcode ModifierOverride}s used to provide held items to enemies on spawn. */
+  readonly OPP_HELD_ITEMS_OVERRIDE: ModifierOverride[] = [];
 
   /**
-   * An array of items by keys as defined in the "modifierTypes" object in the "modifier/modifier-type.ts" file.
-   * Items listed will replace the normal rolls.
-   * If less items are listed than rolled, only some items will be replaced
-   * If more items are listed than rolled, only the first X items will be shown, where X is the number of items rolled.
+   * Override array of {@linkcode ModifierOverride}s used to replace the generated item rolls after a wave.
+   *
+   * If less entries are listed than rolled, only those entries will be used to replace the corresponding items while the rest randomly generated.
+   * If more entries are listed than rolled, only the first X entries will be used, where X is the number of items rolled.
+   *
+   * Note that, for all items in the array, `count` is not used.
    */
-  readonly ITEM_REWARD_OVERRIDE: Array<ModifierTypeKeys> = [];
+  readonly ITEM_REWARD_OVERRIDE: ModifierOverride[] = [];
 }
 
 export const defaultOverrides = new DefaultOverrides();