For those who are unaware of who Trigon is, Trigon is the demon father of Raven and a powerful DC Universe villain. He may not be playable in Injustice Gods Among Us, but is presence is far from non-existent. He is mentioned, referenced and even appears in the classic battle endings of Raven and Scorpion, STARR labs, and Ravens Supermove:
So, why do I believe he will be a major adversary in the possible sequel to Injustice? Well, first of all, in Ravens noncanon ending, she accidently summons Trigon after defeating Superman. Possible hint? Secondly, why is Trigon constantly referenced if he's not playable? And here's the most important reason: in story mode, Wonder Woman asks the parallel universe Raven why she's taking orders from the Regime when her allegiance is with Trigon. Her reply: "Superman's Regime will hasten my father's return." Now that Superman's defeated, with his precious Regime in ruins, could this mean the rise of Trigon?
I'll be interested to here your opinions in the comments below.