With every season premiere of The CW's DC shows, fans can't help but be excited for the unavoidable crossovers between the shows. Showrunners, Andrew Kreisberg and Greg Berlanti has created a robust DC television universe with a lot of possibilities. And now that Supergirl is a part of the universe, their options for crossovers just got interesting.

Although it is really good for the CW to bring in the "big guns" in the coming seasons, this does pose a dilemma as they would have to face a very formiddable threat in the obligatory major crossover that they will have. Bringing in the likes of Supergirl, the Justice Society of America, and now the iconic Superman, would have to mean that Kreisberg and Berlanti will have to up the ante in their crossover episode.

In a report by Entertainment Weekly, Berlanti noted that they had just started planning the four-episode crossover, and information regarding it is being kept on the down low. The first time that a crossover happened, the fomula was doing 1 episodes each for The Flash and Arrow, with each episode dealing with different conflicts. But one things is certain, Kreisberg abd Berlanti will have to do better than Vandal Savage, who was the big baddie of last season's crossover.

Amidst the executive producers' secrecy, fans will still be able to build theories considering all the information. Fans seem to gravitate more to the possibility that the crossover would be the catalyst that brings Supergirl into the same universe. Whether this would be the case still is vague as Supergirl has ended with a huge cliffhanger, which would be far-off from being tied into the Arrow-verse. A report from IBTimes seems to point to having a single villain for the heroes to go up against, and Berlanti seems to allude to that but has yet to give any hints as to who and which show the villain will originate from.