Searinox was a black drake who, just prior to the demonic invasion of the Burning Legion, scoured the uninhabited lands south of Strahnbrad, where he had been feasting on the local farms and their inhabitants for weeks.
Searinox and his brood of whelps came to the knowledge of Feranor Steeltoe and his band of dwarvenDragon Hunters; they wanted to claim the heart of the gargantuan beast. The heart of a black dragon could bestow fiery enchantments upon weapons, and they wanted those enchantments. They saw Searinox hide in his cave and were preparing to attack thinking that he may be vulnerable to a surprise attack.
Then they met with prince Arthas, and with the help of the prince and his warriors the dragon hunters managed to storm Searinox's lair, littered with the hundreds of corpses that he feasted on. Despite Searinox best efforts, he, his whelps, and the undead he summoned were defeated and his rampage was put to an end. Steeltoe reforged the heart into a magical orb, which he gave to Arthas.