Anime movie where a kid dies in a traffic accident and is brought back to life by girl, but with a curse.?

I saw this anime movie sometime around 1998 and 2001. This kid is in a traffic accident and dies, he is then brought back to life by a girl, though he is cursed now. He has to protect the girl and fight these monsters or he dies. He can't die through a normal means and he regenerates his body, as long as the girl is safe he is alive. I need help finding this movie. I never finished watching it back then.