Here's a list of all the items through out the dark world That way we can be prepared for anything that can happen :D
Seam said that it was import I told you about this so here you go!
Location : He told me that you should begin your search at the bottom of card castle
Key Piece 1 : If I remember correctly I believe Seam had the part of the broken key. You should go get it from him!
Key Piece 2 : Remember that puzzle right before the great board? just imput the suit from each floor of card castle from bottom to top and you can get it!
Key Piece 3 : Seam told me to walk where the stars don't shine perhaps it's in the room with that chest you missed?
Oh Im sorry I guess my hints were to vauge. Why don't I just tell you the solutions to the puzzles!
Loaction : to get to the bottom of card castle take the elevator to the prison
Key Piece 1 : if you go to the basement Seam will give you it
Key Piece 2 : The solution is Diamond -> Swap -> Diamond -> Spade -> Swap -> Spade
Key Piece 3 : Remember the room with the danceing scissors? Well you can reach there by going right to the from the bakesale. after that just hug the bottom wall around where the chest is and you will find it!
Here's the Gear I recomend for the battle. Im sure you can do it!
Gear (Kris) : Weapon: Spooky Sword Armor1: Dice Brace Armor2: Amber Card
Gear (Susie) : Weapon: Brave Ax Armor1: Iron Shackle Armor2: Amber Card
Gear (Ralsei) : Weapon: Ragger/Dainty Scarf Armor1: White Riboon Armor2: Amber Card
Items (I recomend saveing as many ReviveMints as you can for a futre battle) : 1 SpinCake 1ClubSandwich 1ReviveMint 1ChocoDiamond 1HeartsDonut 6DarkBurgers
Don't worry Fighting here won't hurt our castle town reputation
Fighting : DevilsKnife (Recomended) : +5At +4Magic & RudeBuster now costs 40TP weapon for Susie
Mercy : Jevil's Tail : +2AT +2DF +2Magic
This should help you!
In the room with the bird shooting at you if you return back to the begining after ringing the bell you will have a fun suprise waiting for you
Legend has it that if you go between the room with the weird tree and the room before there is a rare chance something extta ordinary will happen