Madoka in her canon characterization is... unconventional, but probably closer to 'the Vamp' stereotype. Sensual, sadistic, dangerously smart and cunning.
The incest and hostility amped up the appeal even more, due to the 'forbidden fruit' issue.
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This is the kind of Ichika's dynamic with her in TLR Stratos, being two sides of a coin. When damn near everyone told them "Get a room already or you'll drive us insane!", you know the tension is high enough to power entire I.S.A.
(Since PT in this verse are evilly incompetent and more or less Chaotic good)