Phantasy Star 4

The Algo solar system, somewhere in space... Once a brilliant civilization flourished here. The citizens devoted themselves to art and the sciences, and life was prosperous and good. Then a series of disasters struck. The system-wide management system, 'Mother Brain' was destroyed. So was the first planet, Parma. Over 90% of the system's population died, and the advanced technological culture was lost. Society declined, spiraling downward until at last only a few scattered groups even remembered there once were better times. A thousand years passed. At last, civilization is once more on the rise across the Algo system. People are again turning to thoughts of an easier life. Old knowledge is being rediscovered. But, just as things look brighter, beyond a threshold long thought closed, a dark and very ancient evil stirs...

Your Mission, from the Phantasy Star 4 game manual:

You begin the game as Chaz, an aspiring Hunter straight out of training. Your partner, Alys, is a crafty veteran whose good looks and prowess with the blade have earned her an awesome reputation. Your first assignment, a monster hunt deep in the basement of Motavia Academy, leads to a quest to save Motavia from destruction.