Okay lemme think.. the main character had black hair I believe, and I seen it around 2001-2003ish. The anime style was more of a serious tone, and the art style resembles something like escaflowe, evangelion, and monster. I remember there were three parts of movies of the anime, one where he’s fighting a giant evil dragon, and another where he fights a giant human looking god. He ultimately dies in the end while the city was completely destroyed. The main character has a serious demeanor, like he was waiting for something like this to happen. That’s all I could really remember.
Also to note he transforms to become a giant looking priest not like there was a mech.