"Phantasy Star Portable" is based on Phantasy Star Universe and its latest expansion, Ambition of the Illuminus. The PSP title includes an all-new story mode with added missions and a multi-player mode that supports local multiplayer cooperative play with up to four players. Two new characters have been introduced since Phantasy Star Universe: Vivienne, a CAST whom the main character teams up with throughout the story. Also new to the PSP version is Helga Neumann, a villain who is responsible for terrorist attacks in the Gurhal System.