From 37177809d70f34f1f49e57296189a11591da993e Mon Sep 17 00:00:00 2001
From: fabske0 <192151969+fabske0@users.noreply.github.com>
Date: Mon, 11 Aug 2025 18:09:40 +0200
Subject: [PATCH 1/2] remove `bmg` param

---
 src/battle-scene.ts | 2 +-
 src/field/arena.ts  | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/battle-scene.ts b/src/battle-scene.ts
index 271cde1aaa9..5905cb66cde 100644
--- a/src/battle-scene.ts
+++ b/src/battle-scene.ts
@@ -1514,7 +1514,7 @@ export class BattleScene extends SceneBase {
   }
 
   newArena(biome: BiomeId, playerFaints?: number): Arena {
-    this.arena = new Arena(biome, BiomeId[biome].toLowerCase(), playerFaints);
+    this.arena = new Arena(biome, playerFaints);
     this.eventTarget.dispatchEvent(new NewArenaEvent());
 
     this.arenaBg.pipelineData = {
diff --git a/src/field/arena.ts b/src/field/arena.ts
index 06ba6fdd334..a4744f38769 100644
--- a/src/field/arena.ts
+++ b/src/field/arena.ts
@@ -68,9 +68,9 @@ export class Arena {
 
   public readonly eventTarget: EventTarget = new EventTarget();
 
-  constructor(biome: BiomeId, bgm: string, playerFaints = 0) {
+  constructor(biome: BiomeId, playerFaints = 0) {
     this.biomeType = biome;
-    this.bgm = bgm;
+    this.bgm = BiomeId[biome].toLowerCase();
     this.trainerPool = biomeTrainerPools[biome];
     this.updatePoolsForTimeOfDay();
     this.playerTerasUsed = 0;

From b982de1b9575e44adf24c1c388814a0df38d17a9 Mon Sep 17 00:00:00 2001
From: fabske0 <192151969+fabske0@users.noreply.github.com>
Date: Mon, 11 Aug 2025 18:35:28 +0200
Subject: [PATCH 2/2] apply bertie's suggestion

---
 src/battle-scene.ts | 2 +-
 src/field/arena.ts  | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/battle-scene.ts b/src/battle-scene.ts
index 5905cb66cde..52af0c1b706 100644
--- a/src/battle-scene.ts
+++ b/src/battle-scene.ts
@@ -1513,7 +1513,7 @@ export class BattleScene extends SceneBase {
     return this.currentBattle;
   }
 
-  newArena(biome: BiomeId, playerFaints?: number): Arena {
+  newArena(biome: BiomeId, playerFaints = 0): Arena {
     this.arena = new Arena(biome, playerFaints);
     this.eventTarget.dispatchEvent(new NewArenaEvent());
 
diff --git a/src/field/arena.ts b/src/field/arena.ts
index a4744f38769..34ad8b9e825 100644
--- a/src/field/arena.ts
+++ b/src/field/arena.ts
@@ -54,7 +54,7 @@ export class Arena {
   public bgm: string;
   public ignoreAbilities: boolean;
   public ignoringEffectSource: BattlerIndex | null;
-  public playerTerasUsed: number;
+  public playerTerasUsed = 0;
   /**
    * Saves the number of times a party pokemon faints during a arena encounter.
    * {@linkcode globalScene.currentBattle.enemyFaints} is the corresponding faint counter for the enemy (this resets every wave).
@@ -73,7 +73,6 @@ export class Arena {
     this.bgm = BiomeId[biome].toLowerCase();
     this.trainerPool = biomeTrainerPools[biome];
     this.updatePoolsForTimeOfDay();
-    this.playerTerasUsed = 0;
     this.playerFaints = playerFaints;
   }