The Destroyers were the six planned children of Ares and Hope, however only one was born due to Xena, Gabrielle, Joxer and even Callisto's interference in Dahak's plans.(Xena: Warrior Princess: "Sacrifice II")
Only one of them was born though sometime after Ares saved Hope from the lava pit. It grew very fast, reaching a height of over 7 feet tall in less than a few months. The Destroyer was covered in nasty spikes and was very strong.
The Destroyer was capable of eating any kind of meat, from sheep to humans. Hope kept it in a cave outside Potidaea and came by to check on it and feed it every once in a while, but sometimes it got out to find food for itself. It usually ate livestock, but it eventually progressed to killing humans. The Destroyer could only come out at night though, because it couldn't bear the sunlight. It loved its mother very much and, in spite of its deadly abilities and dark destiny, had a personality like a very young child. It could even speak a little bit.
The Destroyer met its end when Xena came to Potidaea looking for Gabrielle, where she found out about the Destroyer. She tried to fight it, but it was too strong and covered in deadly spikes, so she couldn't get to it. She finally was able to kill it when Gabrielle pretended to be Hope and distracted it while Xena stabbed it in the back. Hope came running in and The Destroyer killed her as it was dying, thinking she betrayed him. (Xena: Warrior Princess: "A Family Affair")