So I read recently that Klaus will be crossing over and it seems like this entire series will be surrounded around The Other Side and helping Bonnie.
If you guys have seen the latest The Orginals episode, we know that Klaus is now all on his own and the mikaelsons have fallen apart.And what they need desperatley is some thing for them to be pulled back together. With TVD Bonnie needs help and very strong magic if she ever has hope of not being the anchor any longer. This is where I think the shows will interlink, the only people that will even consider helping Klaus is his family, maybe not the one's alive but the one's dead. So I have a feeling he will offer someway of realsing Bonnie from being an Anchor if and only she resurructs one of his dead siblings, meaning probably Kol. A lot of people might say, why dont they just swap anchor and then kill the anchor but I believe Tessa will find someway of stopping that and again Bonnie needs a hell of lot of magic to switch anchors.
This is hugely based on some articles I read and also a recent hinting tweet from Nathaniel Buzolic, thanking his fans for their push for Kol to come back and hinted that , quote 'The TVD world have noticed!!" and the way the shows are both going at the moment. I mean if Kol comes back, Klaus will promise to keep him in New Orleans and Bonnie will be free and everyone will techincally get what they want. However I know that this wont be it, a lot of people want the Other side destroyed and many want to bring the viel down, so I think this entire season for TVD will surround that but TO will be a case of bringing The Original family back together, Kol loved his family and I believe he might just be enough despire his crazy impulsivness. He has a lot of potential.