diff --git a/README.md b/README.md
index 01604e04..0831d261 100644
--- a/README.md
+++ b/README.md
@@ -139,6 +139,7 @@ Improved Areas
 - Vermilion City now features Officer Jenny with the Squirtle. She only appears if Pikachu or Eevee are chosen.
 - Rock Tunnel has a more workable map, now being easier to go through and having new areas to explore. Includes a way to get renewable fossils, items, and other interesting bits and pieces. Overall, it makes Flash much more rewarding to bring, showing you where the items and content are instead of being an inconvenience. 
 - Celadon Mansion's Roof House now features Shinjuku Jacky, a cut representation of a famous Virtua Fighter player. The house has also been redesigned, derived from the unused "Grandpa's House", featuring Nintendo 64s.
+	- If you go to the Developer Room after beating the game, Morimoto's boss fight from LGPE will be available!
 - Pokemon Tower was shortened, being less intensive and adding room for more maps.
 - Fuchsia City has been made to resemble the more walkable LGPE version, removing the Cut trees among other things.
 - The Fighting Dojo has been revamped, featuring a design reminiscent of the prototype versions; rough floors, the elder in the back, and more. Additionally, you can now get a Hitmontop as a third option. The Karate Master is also now treated somewhat more like a Gym Leader, having Gym Scaling and a Rematch system. 
diff --git a/constants/hide_show_constants.asm b/constants/hide_show_constants.asm
index 8fd7f807..c45418cd 100644
--- a/constants/hide_show_constants.asm
+++ b/constants/hide_show_constants.asm
@@ -83,6 +83,7 @@ DEF SHOW EQU $15
 	const HS_POKEMON_TOWER_7F_JAMES        ; 44
 	const HS_POKEMON_TOWER_7F_MR_FUJI      ; 45
 	const HS_MR_FUJIS_HOUSE_MR_FUJI        ; 46
+	const HS_MORIMOTO
 	const HS_CELADON_MANSION_EEVEE_GIFT    ; 47
 	const HS_GAME_CORNER_ROCKET            ; 48
 	const HS_WARDENS_HOUSE_ITEM            ; 49 X
diff --git a/data/maps/hide_show_data.asm b/data/maps/hide_show_data.asm
index 704d898e..1d649ce4 100644
--- a/data/maps/hide_show_data.asm
+++ b/data/maps/hide_show_data.asm
@@ -136,7 +136,7 @@ MapHSPointers:
 	dw NoHS
 	dw NoHS
 	dw NoHS
-	dw NoHS
+	dw CeladonMansion3FHS
 	dw NoHS
 	dw CeladonMansionRoofHouseHS
 	dw NoHS
@@ -369,7 +369,9 @@ PokemonTower7FHS:
 	db POKEMON_TOWER_7F, $02, HIDE            ; HS_POKEMON_TOWER_7F_JAMES
 	db POKEMON_TOWER_7F, $03, SHOW            ; HS_POKEMON_TOWER_7F_MR_FUJI
 MrFujisHouseHS:
-	db MR_FUJIS_HOUSE, $05, HIDE              ; HS_MR_FUJIS_HOUSE_MR_FUJI
+	db MR_FUJIS_HOUSE, $05, HIDE              ; HS_MR_FUJIS_HOUSE_MR_FUJI#
+CeladonMansion3FHS:
+	db CELADON_MANSION_3F, $05, HIDE		  ; HS_MORIMOTO
 CeladonMansionRoofHouseHS:
 	db CELADON_MANSION_ROOF_HOUSE, $02, SHOW  ; HS_CELADON_MANSION_EEVEE_GIFT
 GameCornerHS:
diff --git a/data/maps/objects/CeladonMansion3F.asm b/data/maps/objects/CeladonMansion3F.asm
index b4f9c37b..614e34f1 100644
--- a/data/maps/objects/CeladonMansion3F.asm
+++ b/data/maps/objects/CeladonMansion3F.asm
@@ -8,15 +8,16 @@ CeladonMansion3F_Object:
 	warp_event  4,  1, CELADON_MANSION_2F, 4
 
 	def_bg_events
-	bg_event  1,  3, 5 ; CeladonMansion3Text5
-	bg_event  4,  3, 6 ; CeladonMansion3Text6
-	bg_event  1,  6, 7 ; CeladonMansion3Text7
-	bg_event  4,  9, 8 ; CeladonMansion3Text8
+	bg_event  1,  3, 6 ; CeladonMansion3Text5
+	bg_event  4,  3, 7 ; CeladonMansion3Text6
+	bg_event  1,  6, 8 ; CeladonMansion3Text7
+	bg_event  4,  9, 9 ; CeladonMansion3Text8
 
 	def_object_events
 	object_event  0,  4, SPRITE_BIKE_SHOP_CLERK, STAY, UP, 1 ; person
 	object_event  3,  4, SPRITE_CLERK, STAY, UP, 2 ; person
 	object_event  0,  7, SPRITE_SUPER_NERD, STAY, UP, 3 ; person
 	object_event  2,  3, SPRITE_SILPH_WORKER, STAY, NONE, 4 ; person
+	object_event  4,  6, SPRITE_COOLTRAINER_M, STAY, DOWN, 5 ; person
 
 	def_warps_to CELADON_MANSION_3F
diff --git a/data/trainers/parties.asm b/data/trainers/parties.asm
index 5b85faa6..046dd306 100644
--- a/data/trainers/parties.asm
+++ b/data/trainers/parties.asm
@@ -659,8 +659,8 @@ CooltrainerMData:
 ; Viridian Gym
 	db 39, SANDSLASH, DUGTRIO, 0
 	db 43, NIDOKING, 0
-; Celadon Condominiums Moriomoto?
-	db 75, KANGASKHAN, FLAREON, VAPOREON, JOLTEON, MACHAMP, DRAGONITE, 0
+; Celadon Condominiums Morimoto - Team is LGPE's with +10 Levels each.
+	db 64, KANGASKHAN, FLAREON, VAPOREON, JOLTEON, MACHAMP, DRAGONITE, 0
 ; Brunswick Trail / Glade 
 	db 68, RATICATE, POLIWRATH, BUTTERFREE, WIGGLYTUFF, MACHAMP, RHYPERIOR, 0 ; Primo
 	db 67, PIDGEOT, VILEPLUME, GUARDIA, RAPIDASH, SLOWBRO, JOLTEON, 0 ; Trace
diff --git a/scripts/CeladonMansion3F.asm b/scripts/CeladonMansion3F.asm
index 566d7cf5..8619e9ce 100644
--- a/scripts/CeladonMansion3F.asm
+++ b/scripts/CeladonMansion3F.asm
@@ -6,6 +6,7 @@ CeladonMansion3F_TextPointers:
 	dw GraphicArtistText
 	dw WriterText
 	dw DirectorText
+	dw MorimotoFight
 	dw GameFreakPCText1
 	dw GameFreakPCText2
 	dw GameFreakPCText3
@@ -67,3 +68,60 @@ GameFreakPCText3:
 GameFreakSignText:
 	text_far _CeladonMansion3Text8
 	text_end
+
+MorimotoFight:
+	text_asm
+	ld hl, CeladonMansionMorimotoGreeting
+	call PrintText
+
+	call YesNoChoice ; Do they want in?
+	ld a, [wCurrentMenuItem]
+	and a
+	jr nz, .refused
+	
+	ld hl, CeladonMansionMorimotoFight
+	call PrintText
+	ld c, BANK(Music_MeetMaleTrainer)
+	ld a, MUSIC_MEET_MALE_TRAINER
+	call PlayMusic
+	ld hl, wd72d
+	set 6, [hl]
+	set 7, [hl]
+	
+	call Delay3
+	ld a, OPP_COOLTRAINER_M
+	ld [wCurOpponent], a
+	ld a, 11
+	ld [wTrainerNo], a
+	ld a, 1
+	ld [wIsTrainerBattle], a
+	ld hl, CeladonMansionMorimotoDefeated
+	ld de, CeladonMansionMorimotoWin
+	call SaveEndBattleTextPointers
+	jr .done
+.refused
+	ld hl, CeladonMansionMorimotoNo
+	call PrintText
+	; fallthrough
+.done
+	jp TextScriptEnd
+
+CeladonMansionMorimotoGreeting:
+	text_far _CeladonMansionMorimotoGreeting
+	text_end
+
+CeladonMansionMorimotoFight:
+	text_far _CeladonMansionMorimotoFight
+	text_end
+
+CeladonMansionMorimotoNo:
+	text_far _CeladonMansionMorimotoNo
+	text_end
+
+CeladonMansionMorimotoDefeated:
+	text_far _CeladonMansionMorimotoDefeated
+	text_end
+
+CeladonMansionMorimotoWin:
+	text_far _CeladonMansionMorimotoWin
+	text_end
diff --git a/scripts/HallOfFame.asm b/scripts/HallOfFame.asm
index 308ccb40..1b7aee1d 100644
--- a/scripts/HallOfFame.asm
+++ b/scripts/HallOfFame.asm
@@ -251,6 +251,7 @@ ShowThis:
 
 ObjectsToShow:
 	db HS_ROUTE_1_OAK ; Oak post-game fight
+	db HS_MORIMOTO ; LGPE Morimoto Boss Fight
 	db -1 ; end
 
 ObjectsToHide:
diff --git a/text/CeladonMansion3F.asm b/text/CeladonMansion3F.asm
index 714ecf19..42d5703c 100644
--- a/text/CeladonMansion3F.asm
+++ b/text/CeladonMansion3F.asm
@@ -65,3 +65,48 @@ _CeladonMansion3Text8::
 	text "GAME FREAK"
 	line "Development Room"
 	done
+
+; Morimoto Boss Fight from LGPE.
+; We use a mix of quotes from across the series, and adapt it to RBY jargon.
+; Eg. Cooltrainer > Coach Trainer.
+
+_CeladonMansionMorimotoGreeting:: ; LGPE
+	text "I'm MORIMOTO."
+	
+	para "I help out all"
+	line "the COOLTRAINERs."
+;	cont "I have my reasons." this is insanely cringe it's off by ONE CHARACTER
+	
+	para "Do you really want"
+	line "to battle me, the"
+	cont "strongest COOL-"
+	cont "TRAINER?"
+	prompt
+
+_CeladonMansionMorimotoFight:: ; LGPE
+	text "Here I go!"
+	prompt
+
+_CeladonMansionMorimotoNo:: ; USUM
+	text "Oh yeah?"
+	
+	para "Well, that's a"
+	line "real shame. I'm"
+	cont "really good,"
+	cont "after all."
+	done
+
+_CeladonMansionMorimotoDefeated:: ; LGPE, compressed
+	text "When"
+	line "it comes down"
+	line "to it, you are"
+	cont "still the best!"
+	prompt
+
+_CeladonMansionMorimotoWin:: ; BW/BW2, compressed & repositioned
+	text "I am"
+	line "the best, after"
+	cont "all!"
+	
+	para "Just kidding!"
+	prompt