The Battle Chateau (Japanese: バトルシャトーBattle Chateau) is a two-floor building on Route 7 in Kalos where the player can have battles. The types of Trainers that will appear will depend on the noble rank that the player has achieved through their battles in the Chateau.
The player starts out as a Baron or Baroness, depending on their gender, and advances through the ranks of nobility by defeating other noble Trainers. In the initial ranks of nobility, the player's rank is mainly determined by their number of wins, with wins against higher-ranked nobles counting for more than those against lower-ranked nobles. The final rank of Grand Duke or Duchess, however, is only achieved after the player has defeated all regular noble Trainers at least once, including Gym Leaders, the Elite Four and Diantha.
As the player advances in rank, the number of Trainers that appear in the Battle Chateau at the same time steadily grows. Any Trainer that is of the same or lesser rank than the player may appear in the Battle Chateau.
Gym Leaders, the Elite Four, and Diantha are also part of the nobility, holding ranks of Marquis or Marchioness and higher. These Trainers will start to appear in the Battle Chateau after the player has beaten them in the main storyline.
As players rise in rank, there will be a greater access to more writs which can be issued by talking to the lady by the front door. Each writ has its own unique effect. All writs expire at midnight on the day that they are used. Several of the writs can be used at the same time. The silver, gold and black writs all stack together, for example.
Rank first available
Writ of Invitation
A new Trainer appears twice as often (once every 3 minutes).
Silver Writ of Invitation
A new Trainer appears six times as often (once every minute).
Gold Writ of Invitation
Increases battle winnings by 50%.
Writ of Challenge
Increases the levels of Pokémon by 5 (consequently increasing battle winnings).
Blue Writ of Challenge
Decreases the levels of Pokémon by 10 (consequently decreasing battle winnings).
Red Writ of Challenge
Increases the levels of Pokémon by 10 (consequently increasing battle winnings).
Black Writ of Challenge
Increases the levels of Pokémon by 20 (consequently increasing battle winnings).
A new Trainer will periodically replace one of the other Trainers in the Battle Chateau. This may happen when the player enters the Chateau or moves to a different room, as long as at least 6 minutes have passed since a Trainer was last replaced. If multiples of 6 minutes have passed, multiple new Trainers will appear. If the player is changing rooms when a new Trainer appears, the Trainer will be announced, but if multiple Trainers have appeared, only the most recent person will be announced.
When the Writ of Invitation is active, only three minutes must pass before a new Trainer can appear. When the Silver Writ of Invitation is active, only one minute must pass.
Nico, who had already reached the Baron rank, battled against another Baron, Farrell, and won, upgrading his rank into Viscount. Ash then had a battle against Chester, and won, becoming a Baron as a reward. Soon after, Grant challenged Viola to a battle for the highest possible rank: Grand Duke/Duchess. Eventually, Grant's Onix emerged victorious over Viola's Surskit, earning Grant the title of Grand Duke.
The number of wins to achieve each ranking slightly differs in the anime from the games. To achieve Baron or Baroness ranking, the Trainer needs one victory. To become a Viscount or Viscountess, the Baron or Baroness needs ten wins.
The Japanese names of the normal Trainers in the Battle Chateau are derived from various alcoholic beverages and mineral water brands, possibly a reference to how the term chateau can be used to refer to a wine-producing estate.
The prize money coefficient for trainers here (reward divided by Pokémon level) is unaffected by their Battle Chateau rank, only by the underlying Trainer class of their appearance.
With the Black Writ of Challenge enabled, Grand Duchess Diantha becomes the Trainer with the highest-leveled Pokémon in the game, with Pokémon at level 80.
The team of every non-special Trainer in the Battle Chateau consists of Pokémon with identical EV yields, depending on their apparent trainer class. Maids and Furisode Girls give only HP EVs, Monsieurs give Attack, Madames give Defense, Rich Boys give Special Attack, Ladies give Special Defense, and Butlers give Speed.
If the player is female, Grand Dukes do not appear at all.