Keep in mind that PVs are generally going to contain things either from the OP or from the first few episodes. At the point when they made them, they won't have worked on much of the later episodes yet. OPs themselves sometimes hint at characters not shown yet, but they can always modify them half-way through to show extra people. So all that to say: whether a character has or hasn't appeared in a PV shouldn't really be taken to mean anything about the future.
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