This is a black flanged Mace +2 that inflicts double damage to Chaotic clerics (meaning all Chaotic divine spellcasters). When double damage is inflicted the mace flashes with a bright light (no penalties) and makes a loud tearing almost exploding sound. The mace is quite effective in combat but these side effects make it difficult to keep a battle quiet when stealth is needed.
Lore: Force of Law was created centuries ago by a militant order of lawful clerics known as the Guardians of Order who waged war up and down the coast of the Northern Sea. Disdaining stealth they sought open battle with their foes with the intention of eliminating organized bands of chaotics from the region. They were quite successful, bringing a large measure of peace to the region for a century. During this time their numbers dwindled and their vigilance waned and eventually a band of powerful chaotic clerics and assassins infiltrated their fortress-monastery and eliminated them in a single night. Members of the order out on patrol were now the last survivors and they continued their duty with a renewed almost fanatical zeal until the last of them was slain. The Guardians created many powerful weapons, most of them specialized to fight against chaotic creatures. Almost of them were lost in the orders final years after their base was destroyed.