Heroes all  behind him. This scene is identical to the cover of the the comic  "Crisis on Infinite Earths #7", in which Superman is holding the  dead body of Supergirl, with superheroes behind him. The other  similarity to the comic, is that Supergirl therefore no longer  exists in the present day universe of JLU (although is still  remembered), and Supergirl in the comics never existed after  "Crisis" (and was then forgotten).