Board Thread:Questions and Answers/@comment-25202570-20140720071112/@comment-5553481-20140720131120

Shinigami and other 'deities' exist depending on people's beliefs (religions etc), but there is no scientific proof of these deities actually existing.

But no, the shinigami from Bleach are fiction (meaning 'made up'), so don't expect yourself to be wearing a Shihakushō while swinging a Zanpakuto after death.