Books like Iron Body Ninja
Ashida Kim
Iron Body Ninja is 148 pages, about 2 hours 43 minutes at 250 words a minute.
6 books to read next
How long each takes
Naruto 72 3.9 h 
Essence of Ninjutsu 3.3 h 
Martial Arts 3.5 h 
Zen in the Martial Arts 2.6 h 
Book of Ninja 9.7 h 
Naruto 68 3.5 h Bar height shows length. Estimated at 250 words a minute.