Castlevania: Belmont's Curse contains a hidden costume for the main character Rose that transforms her appearance into Sonia Belmont, the protagonist of the original Castlevania Legends on Game Boy. Players can unlock this secret outfit at any point during gameplay by entering a specific button combination known as the Konami Code, a legendary cheat sequence that has appeared in countless games across multiple developers and platforms over decades.
Entering the Konami Code
The process of unlocking the Sonia Belmont skin is straightforward and can be performed from anywhere in the game world. Players should find a safe location, then input the following button sequence on a controller: Up, Up, Down, Down, Left, Right, Left, Right, X, Circle. Those playing on keyboard should use the equivalent inputs: W, W, S, S, A, D, A, D, Shift, and Space. If the code does not work on the first attempt, reversing the final two button inputs may resolve the issue. When successfully entered, an on-screen message will confirm that the outfit has been unlocked.
After receiving the confirmation, players can access their new costume through the game's menu system. Navigate to Options, then select System, followed by Character Skin to equip the Sonia Belmont outfit and begin playing with the new appearance.

Visual Design and Changes
The unlocked Sonia skin represents a dramatic visual transformation for Rose. The outfit replaces her standard appearance with a green, form-fitting leotard inspired by the character concept art from the original Castlevania Legends. The skin also removes Rose's distinctive cursed arm and changes her hair color from orange to blonde, effectively presenting her as an entirely different character. This approach aligns with how Rose's other available costumes function within the game, each drawing inspiration from prominent Castlevania series characters including Trevor, Sypha, and Alucard, and substantially altering her visual presentation to match their respective themes and aesthetics.
Sonia Belmont's Place in Castlevania History
Sonia Belmont originally appeared in Castlevania Legends, released for Game Boy in 1997. The game was initially conceived as the origin story for the Belmont clan's eternal conflict with Dracula, positioning Sonia as the first vampire slayer in the family lineage. However, this narrative was later removed from official series canon following the 2003 PlayStation 2 release of Castlevania: Lament of Innocence, which introduced Leon Belmont as the true founder of the Belmont dynasty and the one who established the family's dedication to hunting Dracula.
Despite her removal from canonical continuity, Sonia remains a significant figure in Castlevania lore as one of the franchise's rare playable female characters. She held the distinction of being the only female protagonist in a mainline Castlevania game until Belmont's Curse launched, which features Rose as its lead character. The inclusion of the Sonia Belmont skin serves as a nostalgic callback to this important but non-canonical chapter of the series' history, allowing modern players to experience a character from the franchise's handheld origins in fully realized modern graphics based on her original character concept art.
