At the end of Friday night's episode, "The Vampire Diaries" ended with the most anticipated return of a character.

Kai is officially on board again and is back to Mystic Falls, his return signifies only one thing: trouble is coming, and Matt became the integral key to saving everyone in Mystic Falls.

Everyone has been alluding of Kai's return in "The vampire Diaries" and fans have shared he is coming back to Mystic Falls. But his sudden return only means one thing, danger is ahead, and a look at the promo recently released, Kai seems to be the one responsible for Elena's return.

Fans are been wondering how he would be able to pull off Elena's return considering the remaining episodes left he's back in. But according to Romper, Elena's anticipated return has something to with the Maxwell bell that rang almost 11 times, which allowed Cade to slip through. Or has something to do with Bonnie's psychic pulse that seems to have caused some magical ramification, Romper has reported.

Kai just sauntered back onto "The Vampire Diaries" in the Friday night episode as if nothing had happened. He straightly walks into a cave below the Armory wherein Alaric and Damon was discussing and planning about killing Cade.

It can be recalled that Kai was the reason why Elena is now on a beauty long sleep after placing a curse on Elena until Bonnie's death. So, everyone is now anticipating that he will be the only one who can bring back Elena on "The Vampire Diaries."

But fans have a feeling that Kai won't bring back Elena, not unless Damon will be willing to do something for him, according to a report on Bustle. The report added that either Kai was brought back due to a mission of killing Cade as redemption or Kai was brought back by the devil.

Another speculation arises in "The Vampire Diaries" that maybe Kai was brought back because of Bonnie's burst of magic the day Enzo died, as per her mother, it opened a door to hell. Delena fans will now be celebrating as, for sure, Damon won't let Kai go unless he wakes Elena up.

Meanwhile, Roerig's character, Matt, is still having a dream of being a hero to his friends, further suggesting that Matt is the integral key in saving everyone in Mystic Falls. Don't miss the final four episodes of Matt, and Elena's return on "The Vampire Diaries."