Board Thread:Theories and Speculation/@comment-3568954-20160718112245/@comment-732150-20160718170046

Hidan's immortality does not require him to perform the rituals regularly. The one thing he needs to remain alive is nutrition, he can be starved to death. This is literally the first sentence on the immortality section of the ability section in his article. He was still considered to be alive by the time of the Fourth Shinobi World War.