What is the assault token in Legend of the Phoenix?

Excuse me, could you please elaborate on the concept of the assault token in the game Legend of the Phoenix? I'm particularly interested in understanding its purpose, how it's acquired, and the strategic value it holds within the gameplay. Are there any specific scenarios or missions where the assault token becomes pivotal? Additionally, does it offer any unique benefits or advantages to the player who possesses it? I'm keen to learn more about this intriguing aspect of the game.