"Batman: Knightfall" is a Realistic CGI Non-Profit Fan-film.
"Batman: Knightfall"'s production is done by only 1 man-Ganesh Karumuri.
The Glorious Pictures or Batman: Knightfall is not affiliated with WB or DC in any manner.
Unable to come up with an idea of their own, the "creator" of Batman: Knightfall decided to simply steal IP belonging to DC for which they have no legal permission to use.