Klaus and Greta Martin shared a non-romantic, working relationship. Klaus supposedly "captured" Greta Martin, but it is likely that she chose to go with him. Her father, Jonas, and brother, Luka, died trying to get her back. Greta told Elena in The Last Day, that Jonas and Luka were "wasting their time. I wasn't lost."
Klaus and Greta were first seen interacting with each other in Klaus. She helps perform a spell to transfer Klaus' spirit back to his own body. In The Sun Also Rises, Klaus and Greta share lots of interaction as she helps him to break the curse. Elena tries persuading Greta to not help Klaus break his curse, as it is Greta's duty to help the servants of nature make sure the curse stays sealed, but Greta replies that her duty is to Klaus only, "the new order".
Klaus and Greta hold the moonstone with one hand each as they destroy it and Klaus kills Jules, Jenna and Elena. Before Jenna's death, she tries to attack Klaus and as Greta heads over towards them, Damon breaks her neck. Klaus' reaction to Greta's death, if any, is unknown.
- Klaus' reaction to Greta's death, if any, is unknown.
- If Klaus had found out about Greta's death, it is unlikely that he would have cared because he only used Greta to break his curse.
- Greta might have had feelings for Klaus in the slightest way, as she showed undying loyalty to him.
- Greta seemed willing to work for Klaus, and quite happy to do so. It is possible that she was in love with him, not only because of her loyalty and affection to him, but also when she said, "Hello, love," to him in Klaus.
- Why she wanted to work for Klaus is unknown, but it is possible that he manipulated her into becoming a mean, evil woman. She would most likely have gone with Klaus willingly.