Brainiac

There are a couple of hints in the movie, Easter Eggs that tease multiple galactic threats in the DCEU. As previously mentioned, the most obvious one is Darkseid. However, just as he did in Man of Steel, Zack Snyder has also teased Brainiac.
In Man of Steel, it’s a blink and you'll miss it scene, when Superman destroys the world-engine. It was just fan-service, a simple nod without any long term consequences. However, Batman v Superman also teases the villain we have so long awaited.

Leaving aside the tasty (and much needed) deleted scene featuring Lex Luthor in the scout ship, there are several references made throughout the entire movie, mostly by the same character. In Batman v Superman, Lex Luthor is hungry for knowledge and he even says that a couple of times. However, this doesn't mean anything until the final scene, in which Lex says that someone is coming and he is hungry.
Now, for what it’s worth, Darkseid will most certainly appear in one of the future Justice League films. However, he isn't known for being hungry for anything, whereas Brainiac is the one villain who always craves more knowledge. And, even better, there are precedents in which the two villains worked together in the comics.
And we can bet that you heard about that movie in which Brainiac and Lex were supposed to be fused into a single uber-villain"¦So yes "“ we believe that Brainiac will arrive in the DCEU, most likely in the (actual) Man of Steel sequel, which is yet to be announced.
Oh, and there is also the Lex OS operating system teased in the marketing campaign that, according to many, sets up the arrival of the Collector of Worlds. Speaking of which"¦
