Callisto's personal Tartarus torture took the form of sticking her in an empty, featureless rock dungeon, leaving her alone with nothing but herself, her thoughts, and the occasional visions of her victims. Later canon hints that she had some level of contact with Hades; this was relatively infrequent, and he didn't have much patience for her. Ares, on the other hand, was a much more frequent visitor. By her canonpoint, they hadn't yet teamed up or started plotting together in earnest, but they'd met; he was intrigued by her and her by him, and he'd started to stop by semi-regularly.