User blog comment:Arachne sama/Shinigami Skills Heredity/@comment-5551986-20130614211615/@comment-8051005-20130615131709

This theory sounds highly plausible, HollowKing, especially since we all know how Kubo loves dropping hints here & there that end up linking to something big later in the story! It is safe to say, anyway, that the skill to control the elements of nature is running in the Shiba family - water (Kaien), fire (Kūkaku and papa Isshin), earth (Ganju).