Quote from Rebekah Mikaelson that perfectly encapsulates Kol and Thena (Their biggest supporter further down in the story)
"A piece of advice big brother, the more one tells you that you can’t have something the more you crave it. Give Kol your support in his feelings for Thena. He has never looked at a woman in the way he does her. You will always choose family…but Kol has never been in love, this will be his first and only choice. Us or her? He will choose her. In your attempt to protect her, you will crush them both. Together they are far more dangerous than Marcel and I were together and we called Mikael to New Orleans! You keep them apart and they will hate you forever. His love for her will turn him into the homicidal maniac you and Nik always mocked him for being. He isn’t you. He won’t fall in love again Elijah. He won't move on from a Tatia to a Katherine, Celeste, Alana, Hayley! She will be the only one. He won’t move on. If he loses her, he will destroy us. We didn’t include him in our promise…Athena is his always and forever."