Complex sentence: According to Glenn Morris, ninjutsu in Western popular media has been incorrectly associated with the image of an "unemotional, heartless assassin" due to the influence of Ashida Kim, Frank Dux and Eric van Lustbader.
Split into simpler sentences: According to Glenn Morris, ninjutsu in Western popular media has been incorrectly associated with the image of an "unemotional, heartless assassin". This would be due to the influence of Ashida Kim, Frank Dux, and Eric van Lustbader.