As an AI language model, I can help you with the game concept and the basic structure of the HTML file. However, creating a fully functioning 3D Battle Royale game like Fortnite would require a significant amount of time, resources, and expertise in game development.
Here's a simplified example of an HTML file that includes JavaScript to create a simple game concept using pictograms:
This example sets up a basic HTML file with a canvas element where the game is rendered. It includes a player object represented by a colored rectangle. The player can be controlled using the Arrow keys on the keyboard, mimicking smartphone operation.
Please note that this is just a starting point and you would need to further develop and expand the game logic, implement 3D rendering, add assets like pictograms, and handle various aspects of a Battle Royale game, which is a complex undertaking.
To create a full-fledged game like Fortnite, it is recommended to use game development frameworks or engines specifically designed for 3D game development, such as Unity or Unreal Engine, rather than sticking to a single HTML file implementation.