How do you be a certain character in Pokemon Mystery Dungeon explorers of sky?

You can't actually choose to be a specific character in Pokemon Mystery Dungeon: Explorers of Sky. You don't get to play as Pikachu, Charmander, or any other specific Pokemon in the game. Instead, the game starts by having you take a personality quiz which determines what Pokemon you become.

Here's how the character selection works:

1. Personality Quiz: When you first start the game, you'll be asked a series of questions about your personality. The answers you choose will determine your starter Pokemon.

2. Starter Pokemon: Based on your answers, the game will select a Pokemon for you. This Pokemon will be your partner throughout your adventure. You'll also get to choose a partner Pokemon, but they will be randomly assigned as well.

3. Customization: While you can't choose your main Pokemon, you can customize its appearance by choosing its gender, fur color, and accessories.

So, you can't directly "be" a specific character like Pikachu. Instead, you'll get to become a unique Pokemon based on your own personality and preferences.