Board Thread:Theories and Speculation/@comment-28345910-20190509230651

For one thing, Itachi shares the same voice actor as Ryoma Nagare from the Getter Robo OVA's, and the same goes for Madara as his teammate Hayato Jin also from the OVA's. Aside from that, Itachi's Susanoo is the same red color as Getter 1/Getter Dragon which Ryoma pilots and Madara's is the same blue color as Liger which Hayato has been known to pilot.

And given that Susanoo like Sasuke and (in-game) Shisui's were mecha references to different ones, this doesn't seem too far-fetched. 