Misdreavus first appeared when Lexi was helping Professor Juniper at Celestial Tower. Misdreavus was revealed to be causing issues which resulted in probelms in the tower. After these were solved, Lexi caught Misdreavus and she joined her team. Misdreavus was then used against Skyla and Drayden.
Misdreavus is often seen to be a quite distant Pokémon, that's quite snobbish towards many other Pokémon. She sometimes lets it's guard down, in which she can be quite silly, usually making other Pokémon laugh.