If you are looking for an archival file (CBZ or PDF) to keep on a tablet or e-reader, enthusiasts usually look for: Internet Archive (archive.org):
Here is a quick guide on how to get the best reading experience without the headache. 1. The Legal (and Easiest) Way
If you can find the official Shueisha colored version, grab it. It breathes new life into the Great Ninja War arc. Storage Check:
Sites like Nyaa are the standard for high-quality "batch" downloads of the manga in .cbz format. 3. Pro-Tips for the Best Experience Format Matters: