Iskath is a city to the north. Further away from the epicenter of the plane crossover anomaly that allows demons to appear but still effected by it. Occasionally a demon will materialize on their own, not bound by any ritual or contract, and cause trouble. Mistress has a knack for resolving these situations, taming the offending parties and occasionally leveraging her natural talents to smooth over political hurdles.

Melody has recently reasserted that she's supposed to be Mistress's apprentice, not just her hand maiden ( see outfit https://satinminions.com/bonus.php?sha=b6b7c2e419 ) and she has talked her way into coming along. Mistress will be on the lookout for any new projects that Melody can take on by herself.

Alison is staying behind because in any kind of intense scenario she'd just be a useless horny liability. Sure, she could be used as a payoff or distraction but that seems a bit cruel after she's softened so much. Plus there's the real danger that if she doesn't get on Torrin's dick soon she might actually explode.