Halo 2: The Characters
The Master Chief returns with a vengeance. Equipped with new Mjolnir Mark VI armor and new weapons the Covenant stand no chance against this walking tank (for now). The Mjolnir Mark VI armor features a remarkably more powerful shielding system and internal supplies of self-injecting biofoam (the player no longer sees a health bar, only the shield bar). It also has the ability to track two weapons' targetting systems at once (enabling dual-wielding for certain small arms).
Cortana, the same "smart" AI from the first game is back. Her apperance has changed slightly, now with longer hair and a bluish body. She shows the same intellect and dry humor, but near the end of Halo 2 she seems... "strange." Some fans thing she is experiencing rampancy.
The child of Captain Jacob Keyes, Commander Miranda Keyes is also the pilot of a UNSC frigate, In Amber Clad. She plays a relatively major role in the story, fighting alongside Sergent Major Johnson and finding Halo-05's Index.