Cross World: Mishiranu Sora no Etatia2005

Enter Kuros, an average high school student who gets sent into another world after getting into a car accident. Losing his memory and forgetting his name, he became known as the Cross Sword hero. In search of a way to open up the Cross Gate to return his own world, Kuros and one of three heroines partner up to travel across the world of Etatia in search of clues. Meanwhile, a mysterious cloaked figure seems intent on disrupting their journey of getting Kuros back to his own world…