HELP desperately trying to remember an anime!

Help please, i am Desperately trying to remember an anime i had several years back but has long since been lost! Okay so here it is, i cant remember the pamagat (obviously) or any character names... It was before 2006, and i had the DVDs which i believe the entire series was only 1 season long. (I may be mistaken). The main points i can recall from the storyline was a boy/ young man is tasked with capturing or killing or something like that all these people on a scroll. So through a series of events it concludes with him discovering that the one that tasked him is actually evil..... That pretty much what i can remember, i want to say the main character was like a lower god or angel or something. One scene that stood out was the main character was told to isda with a needle so he can connect with the isda but not hurt them. If anyone knows then please help... Its become madami of a quest im too stubborn to stop at this point! Thanks!