I definitely recommend you take a look at Leon Chameleon P.I. and the case of the kidnapped mouse by Janet Hurst-Nicholson. It's not exactly the battle book, but it is definitely adventurous, fun and educational. It's a detective story which both my son (5y.o.) and I (32y.o.) both enjoyed a lot. It is geared toward 7-11 year olds, so your son might actually like it. If you use e-readers, you can buy this book both for
the Kindle as well as
Nook (Nook Color offers really nice illustrations, too - I personally read it on Nook Color).