Common demons can be whatever the DM wants them to be, but if we are sticking to official content there are several demons most adventurers encounter with some regularity. These are all from the monster manual. • Dretch, which are the lowest of the low and normally use their great numbers to overpower foes. They do have a special attack: Fetid Cloud (1/Day). A 10-foot radius of disgusting green gas extends out from the dretch. Any creature that starts its turn in that area must succeed on a DC 11 Constitution saving throw or be poisoned until the start of its next turn. • Maralith’s: Giant 4 armed snake women who use swords and overcome their foes with a flurry of blows (They can make 7 attacks with their longswords and tail, one of those is gonna hit!). They also can parry your blows as a reaction: Parry The marilith adds 5 to its AC against one melee attack that would hit it. To do so, the marilith must see the attacker and be wielding a melee weapon. • Balors are probably the most recognizable demons in 5e, armed with flaming whips, flaming swords, and fire! Also, they explode when they die!: Death Throes When the balor dies, it explodes, and each creature within 30 feet of it must make a DC 20 Dexterity saving throw, taking 70 (20d6) fire damage on a failed save, or half as much damage on a successful one. These demons might be “common”, but your players will wish they weren’t dealing with them if they aren’t prepared!