Warning: SPOILERS for the Legacies season 4 and series finale.
The Legacies series finale saw Klaus Mikaelson (Joseph Morgan) show up one last time and gave him and the Mikaelson family as a whole the perfect sendoff. Through four seasons of Legacies, Hope Mikaelson (Danielle Rose Russell) worried about her father, who was deceased. It wasn't as though any harm could befall him; rather, it was that she knew he was stuck in Limbo and couldn't move on to peace until she found her own peace in the world of the living. Even Klaus' long-stalled funeral in Legacies season 4 couldn't fully ease Hope's mind.
Hope had good reason to worry that her father may not find peace. Throughout The Vampire Diaries and much of The Originals, Klaus' emotions, particularly his temper, ruled him, often leading him to make rash decisions and burn bridges. He was volatile, impulsive, and mercurial, regularly lashing out at those close to him. Despite that, his siblings and adopted son, Marcel (Charles Michael Davis), stuck by him and stuck together through the centuries. Family always came first for the Mikaelsons, and no matter what trials they faced, they faced them together.
It's what made Klaus' final speech to Hope from the afterlife in the Legacies series finale so perfect. "My dearest Hope. My littlest wolf. My miracle child," he began before explaining that he had found peace in the afterlife because she, Hope, is his peace. His heartfelt message was full of honest advice: "You will make mistakes–that comes from being a Mikaelson." But what also comes from being a Mikaelson is the unshakeable, unwavering love that each Mikaelson has for one another, despite their fights and betrayals. The Mikaelson siblings may separate, but they always come back together. It's what made Klaus' last words to Hope so inevitable and also so perfect: "I love you so much... Always. And forever." The Mikaelson family's unbreakable vow, "always and forever" has remained the bedrock and foundation of every Mikaelson's life.
The message was one that Hope had desperately needed to hear for years. Her mother, Hayley (Phoebe Tonkin), had been just as important to Hope, but Hope knew her mother had found peace and moved on. She also knew that if she had inherited any villainous tendencies, they almost certainly came from her dad. As much as she feared inheriting her father's worst tendencies, however, Hope loved Klaus fiercely for all his great qualities, too. Klaus was his own worst enemy–but he was also passionate, a fierce protector, funny and charming, and put his family above all other priorities. After Hope died and became Legacies' Tribrid, the greatest unanswered question in Hope's life was whether or not her dad was proud of her and if he was happy after death. His final sign-off, "Always. And forever." gave her all the answers she needed.
His words to her were important for another reason, however. Hope, like Klaus, tended to push everyone who cared about her away. This feeling of loneliness and self-destruction only increased after she became the world's only Tribrid. Klaus telling Hope "Always. And forever." was a reminder to his daughter that she's not alone. She may have lost him. She may have lost Landon. She may have lost (at least for now) Alaric. But she still has her family. Her Aunt Rebekah (Claire Holt) and Aunt Freya (Riley Vogel), her Uncle Kol (Nathaniel Buzolic), and Marcel were all still there for her in the Vampire Diaries spinoff show. They showed her as much in Legacies season 4, episode 15, "Everything That Can Be Lost May Also Be Found," when the four of them staged an intervention to bring her back to her humanity. It's true that Hope lost much in Legacies, but Klaus' words are a reminder and a vow, the perfect ending to the Mikaelsons' story in the Vampire Diaries universe.