Joseph Morgan

The Vampire Diaries' oldest set of siblings is going to experience more strife than ever before.

In one of the final scenes from this season's premiere, a distraught Rebekah (Claire Holt) confronted her brother Klaus (Joseph Morgan) for choosing to save Caroline (Candice Accola) instead of her. When she further retaliated by smashing Klaus' blood bags, he threw her to the ground and said they were done. According to Morgan, that intense argument was only the beginning.

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"Season 4 will ... see that bond tested more than it's ever been," Morgan told us on the Atlanta set of the CW series. "He goes a little further than he's ever gone and [as usual] Klaus likes to ruin everything for himself and push people away."

Even worse, Morgan has to keep his eyes out for Todd Williams, who plays the new vampire hunter. Why? Morgan claims the Vampire Hunter is stealing his thunder! Watch our interview with Morgan below for more of his thoughts on these two new conflicts.

The Vampire Diaries airs Thursdays at 8/7c on The CW.