Hm. How about this?
IC: Cauldron's attack seemed senseless and indiscriminate, but there would prove to be a method to their madness. The cabal sought to harness the power of fear, using the terror generated by their rampaging monsters to fuel their dark rituals. When we went after Cauldron's base, we interrupted these rituals at a critical moment. Even though we thwarted their plot and sent them packing, the uncontrolled dark energy we released in the process hit the surrounding neighborhood instead. The whole area became twisted and cursed, with buildings warping and people changing from the influx of chaotic fear energy. The changes could never be completely reversed, and the area - once known as Jackston, now often referred to as the Haunts - remains a dangerous, strange place to be. Dark magic and creatures left over from the attack still torment the inhabitants, many who were changed themselves by the magic. At night, it's said that living nightmares stalk the streets, feeding on the fears that spawned them...
We couldn't have known what would happen, but we haven't forgotten the cost of our carelessness. It was our first victory together, and it carried a high price.
OOC: I'm thinking we might feel kinda responsible for the Haunts and often patrol there? Perhaps some of us knew people there, making it even more personal? It's more motivation to go after Cauldron, in any case.