According to ComicBook.com on Dec. 3, "Hitman" producer Daniel Alder had tweeted hints that Doomsday, Wonder Woman, and Nightwing were to be the "Batman vs. Superman" film. Recently a Warner Brothers producer had suggested that Robin won't be speaking to Batman and that drones will be appearing in the sequel as well. Also, there had been other tidbits of information going around, too.
Rumors have already been running around suggesting that Nighwing and Wonder Woman may be in the film, but this is the first it's been made apparent of the suggested Doomsday character which was tweeted by Alder.
"Need to talk to some people tonite about #doomsday in #BatmanvsSuperman.” Doomsday really seems like a villain that Warner Bros. would save for either Justice League or a later Superman movie, but maybe the groundwork for his appearance could be laid in Batman Vs. Superman".
It is not entirely sure that Alder is providing this information with any real officialism to it, but fans are indeed getting riled up about hit tweets.
Short time afterwards, Alder clarified the current situation:
"Not speaking as a representative/involved in #BatmanvsSuperman. Just a fan/in the biz/hear things".
For those not familiar with Doomsday, this being was only villain known to have killed Superman in the comic "The Death of Superman" which was published in 1992. The battle between the two took place in Metropolis, however, both Doomsday and Superman both died from their wounds in this featured comic.