The Battle Castle is in the south east of the Battle Frontier. The method of battling within this battle facility is that unlike the other facilities, your Pokémon do not get healed.

As usual, there are three different selections you can go in with; Single or Double Battles & Wireless Mixed. Single allows for 3 on 3 and Double allows for 4 on 4. So if you have teams primed for each particular aspect, then feel free to use your prime selection here

Once you've made your Pokémon selections, you can go on through where you get greeted by the Butler. Whenever you win battles in the battle castle, you earn Castle Points. As you cannot heal your Pokémon, you can exchange the points here for certain perks for use only within this Battle Facility, heal your HP, PP or get an item. The better choices are worth much more Castle Points so its always best to save. The items you buy and the rank ups remain throughout your streak so you do not have to keep doing it after every 7 matches. You CP total also stays throughout your streak.

The options for your own Pokémon are as follows. You also have the ability to check you're Pokémon's current stats, hold item, HP & PP in this screen;

Healing
Function Price Pre-Requisite
Hit Points Heal 10 C.P. -
Power Points Heal 8 C.P. Rank Up - One
Complete Heal 12 C.P. Rank Up - Two
Rank Up - One 100 C.P. -
Rank Up - Two 100 C.P. Rank Up - One
Items

There is also an option for you to to attach items to your Pokémon for a C.P. As items are removed from your Pokemon as you go in, its good to get these for your best competitive strategy. First here are the rank ups for the Items & Berries combined;

Function Price Pre-Requisite
Rank Up - One 150 C.P. -
Rank Up - Two 150 C.P. Rank Up - One
First, we'll cover the berries

Pic Name Function Price Pre-Requisite
Cheri Berry A Poffin ingredient. It may be used or held by a Pokémon to recover from paralysis. 2 C.P. -
Chesto Berry A Poffin ingredient. It may be used or held by a Pokémon to recover from sleep. 2 C.P. -
Pecha Berry A Poffin ingredient. It may be used or held by a Pokémon to recover from poison. 2 C.P. -
Rawst Berry A Poffin ingredient. It may be used or held by a Pokémon to recover from a burn. 2 C.P. -
Persim Berry A Poffin ingredient. It may be used or held by a Pokémon to recover from confusion. 2 C.P. -
Lum Berry A Poffin ingredient. It may be used or held by a Pokémon to recover from any status problem. 5 C.P. -
Sitrus Berry A Poffin ingredient. It may be used or held by a Pokémon to heal the user’s HP a little. 5 C.P. -
Liechi Berry A Poffin ingredient. If held by a Pokémon, it raises its Attack stat in a pinch. 5 C.P. Rank Up - One
Ganlon Berry A Poffin ingredient. If held by a Pokémon, it raises its Defense stat in a pinch. 5 C.P. Rank Up - One
Salac Berry A Poffin ingredient. If held by a Pokémon, it raises its Speed stat in a pinch. 5 C.P. Rank Up - One
Petaya Berry A Poffin ingredient. If held by a Pokémon, it raises its Sp. Atk stat in a pinch. 5 C.P. Rank Up - One
Apicot Berry A Poffin ingredient. If held by a Pokémon, it raises its Sp. Def stat in a pinch. 5 C.P. Rank Up - One
Lansat Berry A Poffin ingredient. If held by a Pokémon, it raises its critical-hit ratio in a pinch. 5 C.P. Rank Up - One
Starf Berry A Poffin ingredient. If held by a Pokémon, it sharply raises one of its stats in a pinch. 5 C.P. Rank Up - One
Occa Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Fire-type attack. 5 C.P. Rank Up - Two
Passho Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Water-type attack. 5 C.P. Rank Up - Two
Wacan Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Electric-type attack. 5 C.P. Rank Up - Two
Rindo Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Grass-type attack. 5 C.P. Rank Up - Two
Yache Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Ice-type attack. 5 C.P. Rank Up - Two
Chople Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Fighting-type attack. 5 C.P. Rank Up - Two
Kebia Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Poison-type attack. 5 C.P. Rank Up - Two
Shuca Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Ground-type attack. 5 C.P. Rank Up - Two
Coba Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Flying-type attack. 5 C.P. Rank Up - Two
Payapa Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Psychic-type attack. 5 C.P. Rank Up - Two
Tanga Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Bug-type attack. 5 C.P. Rank Up - Two
Charti Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Rock-type attack. 5 C.P. Rank Up - Two
Kasib Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Ghost-type attack. 5 C.P. Rank Up - Two
Haban Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Dragon-type attack. 5 C.P. Rank Up - Two
Colbur Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Dark-type attack. 5 C.P. Rank Up - Two
Babiri Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s supereffective Steel-type attack. 5 C.P. Rank Up - Two
Chilan Berry A Poffin ingredient. If held by a Pokémon, it weakens a foe’s Normal-type attack. 5 C.P. Rank Up - Two
Items

You can also get specific items for use within the Battle Castle as well

Pic Name Function Price Pre-Requisite
King's Rock May cause opponent to Flinch 10 C.P. Rank Up - One
Quick Claw The Pokémon holding this may attack first 15 C.P. Rank Up - One
Power Herb Allows user to omit first turn of charge-up required moves; can only be used once 10 C.P. Rank Up - One
Shell Bell User restores 1/8th of maximum HP when damage is inflicted onto the opponent 15 C.P. Rank Up - One
Metronome Raises power of move if used consecutively 10 C.P. Rank Up - One
Light Clay Prolongs effect of Reflect and Light Screen 10 C.P. Rank Up - One
Grip Claw Prolongs number of turns of trapping attacks 10 C.P. Rank Up - One
Big Root Portion of HP recovered increases when using HP-stealing moves 10 C.P. Rank Up - One
Toxic Orb Induces Poison status to holder 10 C.P. Rank Up - One
Flame Orb Induces Burn status to holder 10 C.P. Rank Up - One
Light Ball Pikachu's Special Attack increases by x2 15 C.P. Rank Up - One
Thick Club If attached to Cubone or Marowak, their Attack rises by x2 15 C.P. Rank Up - One
White Herb Cures any status effect; can only be used once 5 C.P. Rank Up - Two
Focus Band May prevent fainting by leaving the user with 1 HP from a KOing move 15 C.P. Rank Up - Two
Focus Sash Leaves 1 HP if hit by a KOing move when HP is full 10 C.P. Rank Up - Two
Leftovers HP Increases by 1/16th each turn 20 C.P. Rank Up - Two
Bright Powder Raises Evasiveness 20 C.P. Rank Up - Two
Scope Lens Increases chances of landing a Critical Hit 20 C.P. Rank Up - Two
Wide Lens Slightly raises accuracy of moves 20 C.P. Rank Up - Two
Zoom Lens Accuracy increases if user is attacked by foe first in a turn 20 C.P. Rank Up - Two
Choice Band Boosts Attack by x1.5, but only allows the use of one attack until the Pokémon is called back 20 C.P. Rank Up - Two
Choice Specs Raises Sp. Attack by x1.5, but only allows the use of one attack until the Pokémon is called back 20 C.P. Rank Up - Two
Choice Scarf Raises Speed by x1.5, but only allows the use of one attack until the Pokémon is called back 20 C.P. Rank Up - Two
Muscle Band Slightly raises power of Physical moves 20 C.P. Rank Up - Two
Wise Glasses Slightly raises power of special moves 20 C.P. Rank Up - Two
Expert Belt Slightly raises power of Super Effective moves 20 C.P. Rank Up - Two
Life Orb Increases attack damage but decreases HP whenever you deal damage 20 C.P. Rank Up - Two
Opponent's Pokémon

You also have the opportunity to see your opponent's Pokémon and the specific stats regarding them. They also cost and are as follows

Function Price
(per Pokémon)
Pre-Requisite
View Species & HP 1 C.P. -
View Item, Nature, Stats & Ability 2 C.P. -
Raise Level by 5 1 C.P. --
Lower Level by 5 15 C.P. --
View Attacks 5 C.P. Rank Up
Rank Up 50 C.P. -

Once done, you go in and battle away. Like the other Battle Facilities, they are done in streaks of 7 before you can exit. Try to get the best streak you possibly can.

Battle Castle Frontier Brain

First Battle

Once you reach a streak of 21 in the Battle Castle, when you go to have your 21sth Battle, you will be challenged by the Frontier Brain of the Battle Castle; Darach. His Pokémon's level match your own. The team he has is not the strongest you will face, but based upon your past battles, if you do not spend CP to heal, you will struggle. Beat him and you get the Silver Medal

Castle Valet Darach

Streak 21
Staraptor Empoleon Houndoom
Second Battle

Continue in on the streak and continue to beat all the Pokémon. Now you have the option to skip battles for 50CP, you may be able to get through it even quicker, should you earn points wisely anyway. As always, the trainers get stronger so you have to be prepared. Once you hit your 49th battle, Darach will re-appear. Beat him to get the Coloured Medal

Castle Valet Darach

Streak 49
Entei Gallade Empoleon