Rather than being a sequel, the game is actually a remake of the first Etrian Odyssey, but with stronger focus on story and characters. The game is set in the land of Etria, with the main character coming from the Highlands.
Etrian Odyssey: Millennium Maiden features a fixed set of characters with changeable class to teach them different skills. New skills can be learned by using skill points, and it's up to the players how to spend these points. Here are some information regarding the characters.
The Hero - He is the main character and a highlander. He uses a spear for a weapon and has been asked by the Etria administration to explore mysterious ruins after an earthquake hit Etria.
Simon Yorke - Simon is a medic and a leader of of an investigation team. He's into the same agenda as the hero, to investigate the ruins after the earthquake. He is described as a calm and capable.
New Etrian Odyssey: Millennium Maiden is scheduled for release on June 27th in Japan for 6,279 yen.