Lake Bul is sited in the northern reaches of the Khizunul mountains. Its shores are a hazardous place to travel and its depths far worse. This is because in the Demon Spawn War, it was stocked with specimens brought over from Abyss.
It is said that Yeenoghu had an insatiable desire for fish and other aquatic delicacies of his abyssal home. When his forces captured the area around lake Bul, he had minions stock the lake with abyssal specimens. As his forces faltered in the Demon Spawn War, they were forced to abandon the eastern tracts of the Clans and his favorite fishery. Some of the things his minions put in the lake were intelligent, like the dim-witted skulvyn. These bestial demons normally haunt the reeking seas of the Abyss. Some out of either lust or macabre mortal experiments, mated with gnolls and other mortal humanoids resulting in a population of aquatic cambions. These half-demons are perhaps the most dangerous foes of lake Bul and the area around it. Over the ages, some have cajoled gnoll tribes into paying tribute and even serving them. An order of demon hunters called the Khalag Narkûn are based out of Dul-Kiz. This organization was established to deal with Bul's demon problem. Demons from this area have been encountered as far away as lake Kapha-Lak.