Superman [Clark Kent; Kal-El]; Batman [Bruce Wayne]; Doctor Christine Gherhard (of S.T.A.R. Labs); Jonathan Kent (origin flashback); Martha Kent (origin flashback); Thomas Wayne (origin flashback); Martha Wayne (origin flashback); Metallo [John Corben] (villain); President Lex Luthor (villain); Major Force [Clifford Zmeck] (cameo); Captain Atom [Nathaniel Adam; Cameron Scott] (cameo); Starfire [Koriand'r; Kory Anders] (cameo in shadows); Black Lightning [Jefferson Pierce] (cameo in shadows); Katana [Tatsu Yamashiro] (cameo in shadows); Green Lantern [John Stewart] (cameo in shadows); Power Girl [Karen Starr] (cameo in shadows)
Superman attacks Metallo who is trashing S.T.A.R. Labs but is put down thanks to the Kryptonite in the villain's body. Superman follows Metallo to Gotham where both he and Batman confront the bad guy as he is looting a graveyard. Metallo shoots Supes with a Kryptonite bullet and, as Batman is trying to extract it from his chest, buries them both in an open grave. Meanwhile, President Luthor lets his troops know that an asteroid from the planet Krypton is hurling towards Earth.