Origin
Nikki is the daughter of Krustax and Soemarina. Living in an undersea castle Alanta, she went for a swim one day, going against the orders of her parents not to leave Alanta. She was chased by Serpentix, a sea serpent which eats mermaids. Nikki swam higher and higher and hid herself in a wreck. There she was attacked by an octopus, but diver Jan van Dieperdale rescued her. Thankful, she followed him on board of his ship. he took her to a travelling circus and put her on display. On the run from evil men who wanted to buy Nikki, his car crashed and was found by Lambik, Suske and Wiske. They took care of Van Dieperdale and Nikki. Upon discovering her true origin, Suske and Wiske brought Nikki back to her parents.
Years later, Nikki and her parents were taken hostage by the Kaarekollen. Suske and Wiske freed them.