Caleb was used to the chaos of battle now. It had taken him a while to get there, but he had been in so many battles now that even the sound of Percy's guns didn't shake his concentration. He kept his attention split between Caduceus and the dragons, vaguely aware of where everyone else was just in case he needed to do something big. The gravity sinkhole hadn't worked the way he wanted and dissipated after just a second, leaving the ground clear beneath Thordak. But it seemed like everyone else was making use of the space and he had at least done something to Thordak. He glanced back over his shoulder at Caduceus, the moment that Percy's gun went off again and struck Thordak in the middle of the chest, and watched as the familiar spell was called up from nature itself. He almost smirked. It was beautiful.
Ice rained from the sky, prickling Thordak's back and sticking into him for a brief moment before melting away. Theo, Caleb thought. It was pretty impressive. Devo'ssa kept battering at Thordak with their wings, driving him further towards the ground, and out of the corner of his eye, Caleb caught Ronan as he jumped forward to release the phoenix from the bottle. The little black fireflies doubled, then tripled, around Ronan as Artagan answered the call for cover with something Caleb had genuinely never seen before. But Archfey, he supposed. Despite the assault of the ice-guardian, Thordak managed to dart out of the way at the last moment, avoiding all but a few scrapes from the phoenix's claws. Caleb was really trying not to hit anything friendly, and he was waiting for the perfect moment, a little window of opportunity. He found it, as Thordak hit the ground and took a moment to right himself. One narrow line of sight.
He held the wall with one hand and reached out with the other, seeing the necrotic energy streaking through the air from Gilmore. He pulled up the same spell, drawing it from the deepest part of himself, and threw it forward with all the strength he had. This time it hit, right in the same spot Percy's bullet had pierced. Thordak's red scales turned black, some flaked and fell off completely as the disintegration rolled across his chest. The screech that Thordak let out rang across the battlefield and he dropped onto his feet, whipping his head towards them. Caleb breathed a soft oh shit oh shit and backed away from the wall, close enough to keep it up but hopefully just out of range.
Artagan and J'mon both released the same spell at nearly the same moment, a vain attempt to keep Thordak in place. The vines that sprouted from the ground were thick, rich, verdant green where Artagan cast them and sand-colored but sprouting with terrible looking thorns where they came from J'mon. And neither one held. It looked for a moment that Artagan's vines might have but they too snapped as Thordak rose up and beat his wings together. He wasn't trying to fly again, he was only battering at the air. But the small windstorm it caused struck the frontline with enough damage to push them back a few feet. Caleb maintained the wall, barely, but only for a moment longer. Thordak unleashed a wave of fiery breath across the battlefield and he braced himself as the wall of ice melted in front of him. He took the brunt of the fire without flinching, holding the next ray of necrotic energy in his palm with a look that almost dared Thordak to hit him again with an element he controlled.