The folk of Faerûn don't normally pray to or acknowledge Bhaal. He is seen as a deeply evil and destructive deity who hungers for death—meaning the death of any sentient beings through unlawful means.
Some people pray to Bhaal when they want to commit murder. A person might have good reason to resort to murder, such as when one is unable to redress some injustice through lawful means. But it's far more common for prayers to Bhaal to be uttered by those who seek to kill someone out of jealousy, greed, or wrath. It's rare for anyone but assassins or compulsive killers to take Bhaal as a patron, and clerics who revere Bhaal often qualify on both counts.
Murder cults of Bhaal have arisen in the past, each led by a charismatic, self-styled priest of Bhaal, but organized worship of the Lord of Murder is extremely uncommon. Temples and shrines are similarly rare. Those who erect a shrine to Bhaal usually do so to thank him for a successful murder. Such shrines typically feature a skull or a severed head surrounded by drops of blood (often both from the murdered victim).
Alignment. Neutral Evil
Realm. Gehenna (Khalas)
Allies. Bane, Loviatar, Talona
Enemies. Chauntea, Helm, Ilmater, Lathander, Lliira, Tyr, most good-aligned deities
Edicts. commit murder at least every tenday as an offering to Bhaal, take pleasure in killing
Anathema. preventing someone from being murdered (unless you murder them after)
Domains. Death
Areas of Concern. murder