In the mid-season finale of The Originals, Rebekah made reference to a secret Marcel has kept from Klaus since 1919. She claims that this secret is so damaging that it would make Klaus hate Marcel forever and Marcel didn’t deny this probable outcome. What could Marcel possibly be hiding from Klaus?

Marcel brought Mikael to New Orleans

Our favorite theory is that Marcel was the one who brought Mikael, aka the Mikaelsons’ father and hunter, to New Orleans. Mikael had been hunting his children for more than one thousand years at this point, and his arrival in New Orleans caused Klaus, Rebekah, and Elijah to flee the home they had built the place they had felt the most at home during their long lives. If Marcel was the one who brought Mikael to the city, perhaps in an attempt to win control of the empire Klaus had built, then we’re not sure if Klaus will ever forgive him. But, kudos to Rebekah for keeping one hell of a secret!

Marcel framed Kol

We know that sometime after the Mikaelsons fled from New Orleans, Klaus neutralized Kol for some reason. We’ve not yet heard this story, but what if it had something to do with the New Orleans debacle? If Marcel not only brought Mikael to New Orleans, but framed Klaus’s brother, Kol, for the whole thing, we’re guessing Klaus might not take too kindly to the information. He’s never been one to admit much guilt over daggering his siblings, but he also doesn’t like it when other people mess with his family.

Marcel stole his favorite necklace

We all know how much Klaus likes his bling. And by bling, we mean the numerous necklaces he always has strung around his neck. They’re subtle, but classic, and we can only imagine what would happen should Klaus lose part of his signature look. New Orleans would fall! If Marcel stole one of Klaus’ prized pieces, could Klaus ever forgive his brother-in-arms (and necklaces)?

What do you think Marcel is hiding from Klaus? Share your theories in the comments below!

The Originals airs Tuesday nights at 8 p.m. ET on The CW.