Katarina was an Interpol officer and a friend of Minako who met her as Sailor V when she followed a Youma to London. She is one of the few civilians that are aware of a senshi's identity. While in London Katarina taught Minako English and acted like a big sister to her. Minako also met a man named Alan in London on whom she developed a crush. Alan wasn't aware that Minako was in love with him, and when he was introduced to Katarina he fell in love with her instead. One day when Katarina and Sailor V were on a case, Sailor V got caught in an exploding warehouse and Katarina was left devastated, thinking her friend was dead. She ran to Alan and took solace in his arms.

In fact, Minako was hiding in the shadows; when she saw Alan and Katarina embrace she realised they'd fallen in love and left, allowing the two to believe she was dead so they could be together. When Katarina heard that Sailor V was operating in Japan again, she came to Japan to find out why Minako hadn't told her she'd survived. However, not long after Katarina met Minako again, Kunzite found her and transformed her into the Youma Papillon. She pursued Minako and, after discovering that she was also Sailor Venus, she attacked her, but Sailor Moon arrived and together they managed to turn Katarina back to normal. Minako explained why she had faked her death and Katarina went back to London, happy to know that Minako was still alive.

(Source: Project WikiMoon)