Here’s a color palette tailored for your 2D pixel-style metroidvania game, focusing on medieval dark fantasy themes with elements of sword and magic:

 <Dark Fantasy Medieval>
1. Blood Red - 
                            
                            #9B1B30
                         - A deep, dark red representing health, danger, and the intensity of combat.
2. Midnight Blue - 
                            
                            #1B2A49
                         - A dark, muted blue that conveys a sense of mystery and the unknown, perfect for backgrounds or borders.
3. Mystic Green - 
                            
                            #4C7B4D
                         - A rich green that symbolizes magic and vitality, ideal for a stamina bar or magical elements.
4. Shadow Grey - 
                            
                            #4A4A4A
                         - A dark grey that can be used for player icons and GUI elements, providing a neutral yet immersive look.
5. Golden Yellow - 
                            
                            #D6A24D
                         - A warm gold that adds a touch of elegance and represents treasure, ideal for highlights and accents.

Color Palette Description:
This palette captures the essence of a dark fantasy world with its deep, rich colors. The Blood Red and Mystic Green create a strong contrast for health and stamina indicators, while the Midnight Blue and Shadow Grey provide a moody backdrop for the user interface. The Golden Yellow adds a sense of reward and wealth, perfect for the medieval theme.

Follow-up Questions:

1. Do you have specific elements in mind for the GUI that you want to emphasize more?
2. Are there any other colors or themes you would like to incorporate into your design?
3. Would you like variations of this palette for different environments or game states?