Klein Clara runs an unlicensed bar within a Nafrece slum, sharing her cramped living space with Eve, Lily Lipman, and three orphan girls—Jessica, Emily, and Charlotte. These children rely entirely on Eve's earnings from perilous underground golf matches. Klein acts as the group's caretaker, managing their household while enduring relentless police harassment demanding protection money and pressure over the bar's rent.

Her history reveals that as a teenager, she and Lily discovered Eve unconscious on Nafrece's streets, suffering a severe head wound. Though Eve healed physically, the injury erased her memories, leaving only her name. Klein took responsibility, sheltering Eve and supporting her training under Leo until his sudden disappearance severed his financial support. Faced with this loss, Klein assumed control of the illegal bar to sustain everyone.

Their situation transforms dramatically after Eve wins a high-stakes "Death match" against Rose. This victory allows the entire group—Klein, Lily, Eve, and the three orphans—to escape the slums. Using part of Eve's winnings, Klein purchases a legitimate establishment, "The White Hart," replacing their illegal operation. She enrolls the orphans in school, and with official documents forged by Vipere, Klein becomes their legal guardian, solidifying their family unit.

On official records, such as Eve's application to the Raiou Academy Golf Team, Klein is formally listed as Eve's guardian, reflecting her enduring protective role within their unconventional family, even after their move to stability.