Freezing mist was a difficult trick. Water vapor would simply desublimate into ice crystals if he tried to materialize it at zero degrees Celsius. The key, therefore, was knowing the triple point of water: that was, the combined measurement of temperature and pressure at which water could exist in any of its solid, liquid, or gas phases.
Pinpointing the temperature was simple enough, but Zeff had always struggled with manipulating the pressure just so. The problem was always atmospheric conditions. The pressure that Zeff applied to his water had to cancel out that which was already being applied by the environment.
But now, his control had moved forward by leaps and bounds, and he was certain that he could manage it, especially in the familiar environmental conditions of Dunehall. He must’ve spent a good third of his youth in this place with Asad.
Zeff manifested his water, and white fog shot across the chamber in billowing chunks. He pressed his soul into it, but he knew it wouldn’t obscure Asad and Caster’s vision. So long as they could see souls, the clouds would only conceal Zeff himself. But that was not the point. He was merely laying the groundwork. Already, Zeff could feel the temperature in the room beginning to plummet.
The rest of his freezing efforts had to be poured onto the Marauder directly. If he acted too carelessly, it would be Asad who was slowed, not Caster. And so Zeff concentrated on creating an endless stream of icy water, locked onto Caster’s soul as it moved through the fog. For extra measure, he threw in a few dozens of flying daggers of genuine ice. Of course they shattered against Caster’s body, but that was just as helpful. So long as Zeff was standing, the cold would follow Caster wherever he went. Even when the Marauder drew close to Asad, Zeff didn’t stop. He merely altered the angle from which the cold struck.