Mabuz

Mabuz the Observant
A decrepitly depicted figure is often the best that one will find for Mabuz, whose worship began in early days when assassins were employed by many. He is symbolized by a blackened skull in most cases, but when taking form has been said to bring about plagues and disasters of the lands. He is revered by assassins as their patron god, and often prayed to that the ill pass peacefully.

He is worshipped rather secretly by most who do so, by burning the skulls of the dead. One skull at the beginning of each year, and then it builds up by burning two the next month, three the month after that, and so on and so forth.