La Santisima Muerte (‘Saint Death’) is a death-spirit, personified as a female skeleton in a cloak, worshipped by its patrons much like any other Roman Catholic saint. However, unlike other saints, Santa Muerte is an unashamedly material icon, prayed to for money, love and vengeance.
I don’t believe Catholics “worship” saints; they worship God, and Jesus, as God, as part of the Holy Trinity. They admire the saints for their immitation of Christ, as models of Christian behavior and for their requested interecession in prayer. As for the drug dealers worshipping a saint of death, nothing more appropos than the wages of sin; death. If they looked deep enough into their “saint” I suspect Satan’s personage would appear. I suppose if you dig into Aztec beliefs, there were plenty of death oriented rituals (human sacrifice), which are probably left over in some of these SOB’s cultural remnants.