diff --git a/src/arena.ts b/src/arena.ts
index 6987cfcdf..978abc147 100644
--- a/src/arena.ts
+++ b/src/arena.ts
@@ -116,7 +116,7 @@ export class Arena {
       return this.randomSpecies(waveIndex, level, (attempt || 0) + 1);
     }
 
-    const newSpeciesId = ret.getSpeciesForLevel(level, true);
+    const newSpeciesId = ret.getSpeciesForLevel(level, true, false, isBoss);
     if (newSpeciesId !== ret.speciesId) {
       console.log('Replaced', Species[ret.speciesId], 'with', Species[newSpeciesId]);
       ret = getPokemonSpecies(newSpeciesId);
diff --git a/src/data/pokemon-species.ts b/src/data/pokemon-species.ts
index 41c2758c8..b4d000e4d 100644
--- a/src/data/pokemon-species.ts
+++ b/src/data/pokemon-species.ts
@@ -344,7 +344,7 @@ export default class PokemonSpecies extends PokemonSpeciesForm {
     return this.name;
   }
 
-  getSpeciesForLevel(level: integer, allowEvolving?: boolean, forTrainer?: boolean): Species {
+  getSpeciesForLevel(level: integer, allowEvolving: boolean = false, forTrainer: boolean = false, isBoss: boolean = false): Species {
     const prevolutionLevels = this.getPrevolutionLevels();
 
     if (prevolutionLevels.length) {
@@ -379,9 +379,11 @@ export default class PokemonSpecies extends PokemonSpeciesForm {
       if (!forTrainer && isRegional)
         evolutionChance = 0;
       else if (ev.wildDelay === SpeciesWildEvolutionDelay.NONE) {
-        evolutionChance = Math.min(0.5 + easeInFunc(Math.min(level - ev.level, 40) / 40) / 2, 1);
+        const maxLevelDiff = forTrainer || isBoss ? forTrainer && isBoss ? 10 : 20 : 40;
+        const minChance = forTrainer ? 0.5 : 0.75;
+        evolutionChance = Math.min(minChance + easeInFunc(Math.min(level - ev.level, maxLevelDiff) / maxLevelDiff) * (1 - minChance), 1);
       } else {
-        let preferredMinLevel = (ev.level - 1) + ev.wildDelay * 10;
+        let preferredMinLevel = (ev.level - 1) + ev.wildDelay * (forTrainer || isBoss ? forTrainer && isBoss ? 5 : 10 : 20);
         let evolutionLevel = ev.level > 1 ? ev.level : Math.floor(preferredMinLevel / 2);
 
         if (ev.level <= 1 && pokemonPrevolutions.hasOwnProperty(this.speciesId)) {
@@ -413,7 +415,7 @@ export default class PokemonSpecies extends PokemonSpeciesForm {
 
     for (let weight of evolutionPool.keys()) {
       if (randValue < weight)
-        return getPokemonSpecies(evolutionPool.get(weight)).getSpeciesForLevel(level, true);
+        return getPokemonSpecies(evolutionPool.get(weight)).getSpeciesForLevel(level, true, forTrainer, isBoss);
     }
 
     return this.speciesId;
diff --git a/src/data/trainer-type.ts b/src/data/trainer-type.ts
index f7ea4fe83..9bbd4b872 100644
--- a/src/data/trainer-type.ts
+++ b/src/data/trainer-type.ts
@@ -549,7 +549,7 @@ function getGymLeaderPartyTemplate(scene: BattleScene) {
 
 function getRandomPartyMemberFunc(speciesPool: Species[], postProcess?: (enemyPokemon: EnemyPokemon) => void): PartyMemberFunc {
   return (scene: BattleScene, level: integer) => {
-    const species = getPokemonSpecies(Phaser.Math.RND.pick(speciesPool)).getSpeciesForLevel(level, true, true);
+    const species = getPokemonSpecies(Phaser.Math.RND.pick(speciesPool)).getSpeciesForLevel(level, true, true, scene.currentBattle.trainer.config.isBoss);
     const ret = new EnemyPokemon(scene, getPokemonSpecies(species), level, true);
     if (postProcess)
       postProcess(ret);
@@ -561,7 +561,7 @@ function getSpeciesFilterRandomPartyMemberFunc(speciesFilter: PokemonSpeciesFilt
   const originalSpeciesFilter = speciesFilter;
   speciesFilter = (species: PokemonSpecies) => allowLegendaries || (!species.legendary && !species.pseudoLegendary && !species.mythical) && originalSpeciesFilter(species);
   return (scene: BattleScene, level: integer) => {
-    const ret = new EnemyPokemon(scene, getPokemonSpecies(scene.randomSpecies(scene.currentBattle.waveIndex, level, false, speciesFilter).getSpeciesForLevel(level, true, true)), level, true);
+    const ret = new EnemyPokemon(scene, getPokemonSpecies(scene.randomSpecies(scene.currentBattle.waveIndex, level, false, speciesFilter).getSpeciesForLevel(level, true, true, scene.currentBattle.trainer.config.isBoss)), level, true);
     if (postProcess)
       postProcess(ret);
     return ret;
diff --git a/src/trainer.ts b/src/trainer.ts
index 0daddda59..1f46e9fdf 100644
--- a/src/trainer.ts
+++ b/src/trainer.ts
@@ -136,7 +136,7 @@ export default class Trainer extends Phaser.GameObjects.Container {
       }
 
       const species = template.isSameSpecies(index) && index > offset
-        ? getPokemonSpecies(battle.enemyParty[offset].species.getSpeciesForLevel(level, false, true))
+        ? getPokemonSpecies(battle.enemyParty[offset].species.getSpeciesForLevel(level, false, true, this.config.isBoss))
         : this.genNewPartyMemberSpecies(level);
       
       ret = new EnemyPokemon(this.scene, species, level, true);
@@ -163,7 +163,7 @@ export default class Trainer extends Phaser.GameObjects.Container {
     } else
       species = this.scene.randomSpecies(battle.waveIndex, level, false, this.config.speciesFilter);
 
-    let ret = getPokemonSpecies(species.getSpeciesForLevel(level, true, true));
+    let ret = getPokemonSpecies(species.getSpeciesForLevel(level, true, true, this.config.isBoss));
     let retry = false;
 
     console.log(ret.getName());
@@ -181,7 +181,7 @@ export default class Trainer extends Phaser.GameObjects.Container {
       console.log('Attempting reroll of species evolution to fit specialty type...');
       let evoAttempt = 0;
       while (retry && evoAttempt++ < 10) {
-        ret = getPokemonSpecies(species.getSpeciesForLevel(level, true, true));
+        ret = getPokemonSpecies(species.getSpeciesForLevel(level, true, true, this.config.isBoss));
         console.log(ret.name);
         if (this.config.specialtyTypes.find(t => ret.isOfType(t)))
           retry = false;