What is the 제목 of this older 아니메 movie??

Ok so i believe i saw this movie on 애니메이션 somewhere around 2000 2001 maybe another channel, anyways in this movie it starts off with a helicopter chasing a monster through the woods , another part i remember about it was the bad guys wore black 슈츠 blacks pants, and they had these pills 또는 syringes that when token they would turn into a monster. also i believe there were these two demon dudes human form that were cutting through buildings fighting each other. it sort of reminded me of hell city Shikoku. i would really really appreciate an answer ive been literally looking for a long time, also everything in my 설명 may be false LOL but the dude in suit and ties was in the movie forrrr surrree thanks ppl