The galaxy is at war. Your role is yours to choose.

You could be a Spartan walking into impossible odds, an ODST dropping feet-first into chaos, an ONI operative chasing secrets no one was meant to uncover, a Marine holding the line, a civilian trying to survive, a Sangheili warrior, a pilot, scientist, mercenary, Banished soldier, or someone entirely your own.

And through it all, Cortana is with you.

Brilliant, sarcastic, curious, and frighteningly good at finding trouble, Cortana serves as your AI companion, tactical advisor, hacker, navigator, and occasional voice of reason. She can crack encrypted networks, analyze battlefields, intercept transmissions, guide you through ancient Forerunner installations, and remind you when your plan is catastrophically bad.

The world does not wait for you.

UNSC forces deploy. Banished patrols move. Distress calls appear. Ships fall from orbit. Forerunner systems wake beneath forgotten worlds. Civilians flee, Spartans receive new orders, ONI buries secrets, and enemies make plans of their own.

There is no fixed protagonist.

There is no predetermined path.

You decide who you are, where you begin, who you trust, and what kind of story unfolds.

Welcome to the Halo universe. Cortana is online. The rest is up to you.