UPDATE: These are now available for pre-order exclusively at Walmart.
McFarlane has announced a wave of DC Multiverse based on the Dark Knights Metal. The Dawnbreaker, The Devastator, The Murder Machine, & The Grim Knight will make up this wave. However, since these figures show up in the toy aisle, to avoid having a package say “Murder Machine”, they will likely be referred as Batman Earth-32, Batman Earth-1, Batman Earth-44.
There is no set release date for these yet, but the should be available in the next 3-4 months.
