>I seem to recall Patchouli calling Remilia an old friend, but beyond
>that who knows what their relationship is or what's going to happen. I
>kind of expect critical unfinished business, considering how fast she
>dropped everything to go chase down Remilia.
>
>Could she have been involved in the attack on Scarlet House?
>

Based on what I've seen in this episode, I'd guess that she wasn't involved.

A rough outline:
She went to see her best friend the morning after the attack, and there was nothing there. After investigating, she assumed that the mission to kill the Scarlets had been wholly successful, finished mastering the Abandonments, and eventually found her way to the Great Library.

Peter Eng
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Insert humorous comment here.