You're a Vision With Nowhere to Go
From a young age, Klaus was taught that his own ideas didn't matter- that his emotions, thoughts, and desires were unimportant, wrong, and a "distraction". He was told to tamp down on his sense of self- after all, it was of utmost importance that he fit the mold created by his Dad for all of his children to fill.
But someone helped him realize how wrong that was. They encouraged him to be better, to reach for what he wanted, to take what Reginald said with a grain of salt. They cheered him on the whole way through, was there when he needed someone the most. They would get him out of his mind, when he couldn't bare to be in it anymore. They were one of his most dearly loved people. In return, Klaus became one of theirs.
or
For a long time, Klaus had believed Ellie was a ghost.
