Board Thread:Theories and Speculation/@comment-30323490-20170305205254/@comment-26104757-20170307005718

More specifically, is it considered an outside power if the Sage Mode user is similar to Jiraiya and Kabuto?

Jiraiya, although gathers natural energy before he summons the elder Toads, relies on their assistant to maintain it.

Kabuto was given a bite mark by the White Snake Sage to acquire his Sage Mode, (I think).

Both did train for it, though. But I'm unsure if this is a result of their own efforts, or the efforts of others.