Senpou: Inton Raiha - Raiton and Inton mixed together to form a branched dangerous lightning network . The flashes can be fired from both hands simultaneously. Senpou: Inton Raiha uses Sage of Six Path's chakra. And till now there have been only 4 characters to use Sage of Six Path's chakra - Obito, Madara, Naruto and Sasuke. It is highly unlikely that Third raikage knew/believed in Rikudou Senin let alone had his chakra.

Also Third raikage's black lightening was unique to him and later used by Darui too and it is shown that it can be used at a single target at a time. It covers the whole body of the user while Senpou: Inton Raiha comes out from hands of user.