HOW TO DROP THE RANK 9 ASSAULT RIFLE AR NINJA 3
AR Ninja 3 is considered one of the best Assault Rifle in the game together with Blue Rose MK3.
AR Ninja 3 is dropped by Makai Type XX in the Demon Cave so all you have to do is...gather a lot of patience and start your farming against this boring boss
I usually kill Makai Type XXX first (the blue one) since he gets too fast if he's the last one standing, but that's a matter of tastes I guess.
For a detailed walkthrough check the video below: