diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index c50d801b18..b1ce7f964b 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -7504,6 +7504,12 @@ static u32 GetTrainerMoneyToGive(u16 trainerId)
                 lastMonLevel = party[gTrainers[trainerId].partySize - 1].lvl;
             }
             break;
+        case F_TRAINER_PARTY_EVERYTHING_CUSTOMIZED:
+            {
+                const struct TrainerMonCustomized *party = gTrainers[trainerId].party.EverythingCustomized;
+                lastMonLevel = party[gTrainers[trainerId].partySize - 1].lvl;
+            }
+            break;
         }
 
         for (; gTrainerMoneyTable[i].classId != 0xFF; i++)
diff --git a/src/battle_setup.c b/src/battle_setup.c
index 220edd394a..2b8e63e766 100644
--- a/src/battle_setup.c
+++ b/src/battle_setup.c
@@ -798,6 +798,14 @@ static u8 GetSumOfEnemyPartyLevel(u16 opponentId, u8 numMons)
                 sum += party[i].lvl;
         }
         break;
+    case F_TRAINER_PARTY_EVERYTHING_CUSTOMIZED:
+        {
+            const struct TrainerMonCustomized *party;
+            party = gTrainers[opponentId].party.EverythingCustomized;
+            for (i = 0; i < count; i++)
+                sum += party[i].lvl;
+        }
+        break;
     }
 
     return sum;
diff --git a/src/battle_tower.c b/src/battle_tower.c
index 9300756561..a4758b9304 100644
--- a/src/battle_tower.c
+++ b/src/battle_tower.c
@@ -23,6 +23,7 @@
 #include "field_message_box.h"
 #include "tv.h"
 #include "battle_factory.h"
+#include "constants/abilities.h"
 #include "constants/apprentice.h"
 #include "constants/battle_dome.h"
 #include "constants/battle_frontier.h"
@@ -3007,6 +3008,7 @@ static void FillPartnerParty(u16 trainerId)
     u16 monId;
     u32 otID;
     u8 trainerName[(PLAYER_NAME_LENGTH * 3) + 1];
+    s32 ball = -1;
     SetFacilityPtrsGetLevel();
 
     if (trainerId == TRAINER_STEVEN_PARTNER)
@@ -3098,6 +3100,53 @@ static void FillPartnerParty(u16 trainerId)
                 }
                 break;
             }
+            case F_TRAINER_PARTY_EVERYTHING_CUSTOMIZED:
+            {
+                const struct TrainerMonCustomized *partyData = gTrainers[trainerId - TRAINER_CUSTOM_PARTNER].party.EverythingCustomized;
+
+                CreateMon(&gPlayerParty[i], partyData[i].species, partyData[i].lvl, 0, TRUE, j, TRUE, otID);
+                SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &partyData[i].heldItem);
+
+                // TODO: Figure out a default strategy when moves are not set, to generate a good moveset
+                for (j = 0; j < MAX_MON_MOVES; ++j)
+                {
+                    SetMonData(&gPlayerParty[i], MON_DATA_MOVE1 + j, &partyData[i].moves[j]);
+                    SetMonData(&gPlayerParty[i], MON_DATA_PP1 + j, &gBattleMoves[partyData[i].moves[j]].pp);
+                }
+                SetMonData(&gPlayerParty[i], MON_DATA_IVS, &(partyData[i].iv));
+                if (partyData[i].ev != NULL)
+                {
+                    SetMonData(&gPlayerParty[i], MON_DATA_HP_EV, &(partyData[i].ev[0]));
+                    SetMonData(&gPlayerParty[i], MON_DATA_ATK_EV, &(partyData[i].ev[1]));
+                    SetMonData(&gPlayerParty[i], MON_DATA_DEF_EV, &(partyData[i].ev[2]));
+                    SetMonData(&gPlayerParty[i], MON_DATA_SPATK_EV, &(partyData[i].ev[3]));
+                    SetMonData(&gPlayerParty[i], MON_DATA_SPDEF_EV, &(partyData[i].ev[4]));
+                    SetMonData(&gPlayerParty[i], MON_DATA_SPEED_EV, &(partyData[i].ev[5]));
+                }
+                if (partyData[i].ability != ABILITY_NONE)
+                {
+                    const struct SpeciesInfo *speciesInfo = &gSpeciesInfo[partyData[i].species];
+                    u32 maxAbilities = ARRAY_COUNT(speciesInfo->abilities);
+                    for (j = 0; j < maxAbilities; ++j)
+                    {
+                        if (speciesInfo->abilities[j] == partyData[i].ability)
+                            break;
+                    }
+                    if (j < maxAbilities)
+                        SetMonData(&gPlayerParty[i], MON_DATA_ABILITY_NUM, &j);
+                }
+                SetMonData(&gPlayerParty[i], MON_DATA_FRIENDSHIP, &(partyData[i].friendship));
+                if (partyData[i].ball != ITEM_NONE)
+                {
+                    ball = partyData[i].ball;
+                    SetMonData(&gPlayerParty[i], MON_DATA_POKEBALL, &ball);
+                }
+                if (partyData[i].nickname != NULL)
+                {
+                    SetMonData(&gPlayerParty[i], MON_DATA_NICKNAME, partyData[i].nickname);
+                }
+                CalculateMonStats(&gPlayerParty[i]);
+            }
             }
 
             StringCopy(trainerName, gTrainers[trainerId - TRAINER_CUSTOM_PARTNER].trainerName);
diff --git a/src/match_call.c b/src/match_call.c
index a9d18b3477..c3378040e3 100644
--- a/src/match_call.c
+++ b/src/match_call.c
@@ -1812,6 +1812,9 @@ static void PopulateSpeciesFromTrainerParty(int matchCallId, u8 *destStr)
     case F_TRAINER_PARTY_CUSTOM_MOVESET | F_TRAINER_PARTY_HELD_ITEM:
         speciesName = gSpeciesNames[party.ItemCustomMoves[monId].species];
         break;
+    case F_TRAINER_PARTY_EVERYTHING_CUSTOMIZED:
+        speciesName = gSpeciesNames[party.EverythingCustomized[monId].species];
+        break;
     }
 
     StringCopy(destStr, speciesName);