Fire and Ice
Fire and Ice was an event that marked the end of a Chapter of the Warriors of Destiny event cycle.
Basically, Casca gathered people together in the City of Yew, and announced that he had found a way to end the invasions of the Shadowlord Armies (see War of Shadows). Casca then led the intrepid warriors to a Dungeon, specifically Hythloth on most Shards. More monsters than usual met the warriors as they made their way through the dungeon, looking for things that shouldn't be there. Eventually, a crystal formation was discovered. Casca attempted to destroy the crystals via a combination of casting various magics and bashing it with his staff. (This part of the event appears to have been written for comic effect.)
Eventually, the crystal was destroyed. (Exactly how this was achieved was, perhaps purposefully, not clear.) The warriors and their King then returned to Yew, wherein Casca boasted of his achievement. Casca's exact words, and levels of arrogance, varied by shard.
The exact meanings of the event were unclear. However, these events, message board posts by representatives of the game manufacturer, and subsequent official fiction raise the possibility that the people of Sosaria are caught in the middle of some kind of blood feud between warring, ancient dragon races. In effect, the Shadowlords, while still the primary villain of the Warriors of Destiny storyline, were not the only independent threat.