- "The deities of Toril take an active interest in their world, channeling power through their clerics, druids, rangers, paladins, and other worshipers and sometimes intervening directly in the affairs of mortals. At the same time, they plot war, intrigue, and ally among themselves, between themselves and powerful mortals, and with extraplanar being such as elemental rulers and demons. In this they resemble their mortal worshipers, for to an extent deities are defined and shaped by their worshipers, their area of interest, and their nature -- for many deities are actually mortals who have gained the divine spark. Because they lose strength if their worship dwindles away and is forgotten, deities task their clerics and others to whom they grant divine spells with spreading their praise and doctrine, recruiting new worshipers, and keeping the faith alive." -- Forgotten Realms Campaign Setting
A deity is a being of great power that controls some aspect of mortal affairs, referred to as the god's portfolio.