What expectations do you have about Tartuffe before he appears?

There is a certain sense in which Tartuffe's shadow hangs mysteriously over the play until his entrance in the third Act. We know that Madame Pernelle and Orgon seem to love him (and have evidence for doing so), but Dorine, Damis, and Cleante all seem to know that he is a fraud. Therefore his identity is somewhat mysterious--in a bad way.