Can you name this anime?

[Chromium_Steel]

Hi I was wondering if anyone might be able to help me find an anime that I saw a long time ago.

 

If memory serves the anime was an OVA and was about a man who finds this child and comes to this town in a desert which looked to be circular and had a big wall around it, he was a bit of a wonderer character. Anyway he basically felt that something was wrong he then found out that there was a miracle worker there that had been bringing everyone back to life even after a terrible disease had afflicted the town. In the end he kills everyone so that they can rest in peace leaving only the child that he encountered at the start, the child then realises that he/she (I can’t remember which) is also dead and kills himself/herself and the main character is seen wondering back into the dessert.  I believe that the main character had a gun and possibly a sword.

 

I’m also 90% sure that it was a dub

 

I know that this is a pretty vague description and that the details are sketchy at best but I really would like to find out what this is and any help would be greatly appreciated.