It's hard to think Kazuma Kuwabara has a sister: let alone an older one who's even more skilled than he. Like Kazuma, Shizuru's got a very strong spiritual sense (we see this when Shizuru is able to see the secret message on Koenma's videotape). She's also supposedly a kick-butt fighter (everyone seems scared to tick her off, especially Kazuma).

She just doesn't show her true colors very often. She's normally the coolest cucumber in the whole gang (her typical response to anything is to just continue smoking her cigarette), though there are moments when she'll flare up. As to her relationship with her little brother, it's hard to say. When Kazuma disappeared, she helped Keiko to bully Botan into revealing the secret of the Dark Tournament [Ankoku Bujutsukai]. She acts like a mother to her little brother, making sure he tries to get a life. But when Keiko asks why she doesn't react while Kazuma is getting beaten up during the tournament, Shizuru seems to not care. It's simply because she knows she can't do a thing about it under the rules. She's not the kind to fight fate. She is concerned, but she also knows that hysterics go nowhere.

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