User blog comment:Uraharattack/Question on Page 16 Chapter 225 - Blackbeard Theory/@comment-221.127.168.214-20180202121231

Darkness is one that absorbs everything! Hence, he can have more than 1 devil fruit.

stealing is rather like - knowing where the DF is in the body of the DF user / something like cannibalism, and getting it physically! (i.e. stealing is not from fruit but using is)