Jul 4 2009 12:54 PM Mion ..... I never seen she play killer role in series. But she do directly cause someone get kill. Mostly her action like her lamentation to Shion that she not manage to attract Keichi interest flag ..... then later raising Shion negative feeling. Then again, the trigger is actually Keichi doll ... if Keichi give it to Mion, none will happen.
But later Mion not inform Shion that none of head family involve in so called Oyashiro curse causing Shion to think Satoshi killer is among high rank of family. Mion also capable to stop the first arc incident if she inform Keichi about Oyashiro curse case, she and Rena don' have to die.
Another situation, Mion could save Satoko faster if she manage to get her grandma straight and Keichi don't need to kill Satoko's uncle.
In other word, nobody is innocent. Any of them might start something. But Mion not killing anyone with her very hand. Only Shion do the kill personally. The answer arc of first season explain it.