In the world of Dragon Age, demons are some of the biggest threats you'll face. They're also a huge part of the worldbuilding, responsible for the widespread discrimination against mages. Put simply, demons are spirits of the Fade that have had their purpose twisted. Spirits generally represent a virtue such as courage or justice, while demons align with negative human emotions.
The goal of most demons is to feed off of the negative feelings of humans. Many try to possess people, specifically mages, in order to enact their will in the physical world. They can be fearsome opponents, but some moreso than others. Here are all the types of demon ranked from worst to best.
These are some of the weakest kind of demons in existence. They may not be strictly "demons" at all. Instead, wraiths seem to be what remains after a powerful spirit or demon have been destroyed. They lack the ability to possess the living or dead and seem unable to cross into the physical world without help. They're only capable of using magic to attack when in the presence of a more powerful demon that can "charge" them. Overall, not the most threatening creature.
Shades are strange among the ranks of demons. While most seek to possess humans, living or dead, a shade is the result of a demon that wasn't able to or even chose not to. Instead, after crossing over into the physical world, they drift around like an invisible cloud of bad vibes. They feed off the psyche of any living being it encounters. Eventually, when a shade has absorbed enough energy, they can physically manifest as blobby, vaguely humanoid creatures.
It's thought that the act of crossing over from the Fade to the physical world can leave a demon so confused that can't possess anything. Shades may, in fact, still think they're in the Fade and feeding off the energy of other spirits. They're a common enemy throughout the series and you'll get good at putting them down.
The most common and lowest-ranked of the proper demons, these embody the simple emotion of anger. The complexity of the emotion they're bound to generally dictates a demon's power, and so rage demons are less formidable than those of envy or desire. They're also less intelligent. Rage demons don't plot, they strike. The true form of these demons in the Fade are creatures of fire, resembling lava, and they can attack with flame. Since these guys are everywhere, it might be time to invest in some fireproof pants.
Terror demons are also low ranked spirits and are generally subservient to more powerful fear-based demons. They seek to inspire only the most basic kind of fear in their enemies: the kind that has you run away screaming. They're rarer than rage demons and look much cooler, but they probably won't give you any significant trouble on their own. Their one unique ability gives them the power to phase in and out of the Fade, popping out of thin air to surprise enemies. They're basically just the demonic embodiment of a jump scare.
You encounter demons of sloth very rarely in the Dragon Age games and hardly ever in straight-up combat. This is because sloth demons have no desire to fight or kill. They're known as masters of disguise, able to take on many forms and even change the appearance of their environment in order to deceive their victims.
You usually find them as masterminds behind larger plots rather than simple enemies to be cut down. For example, a sloth demon (so powerful that its name is just "Sloth") is responsible for the infiltration of the Circle Tower in Dragon Age: Origins and the grueling Fade quest takes place in its domain.
These are the more powerful demons that rule over the lesser demons of Terror. They resemble a kind of witch mixed with a giant spider, with a set of clawed insect legs emerging from its back. Generally speaking, Fear demons aren't the most powerful or complex. Fear is, after all, a very base, primal emotion. Some just mimic the forms they see in mortal nightmares, hoping to inspire a sharp shock of fear. Unfortunately, humans make everything more complicated and our more refined fears—fear of the future, fear of failure—make fear demons more powerful.
Envy demons are one of the rarest kind and are definitely the most freaky looking. They also have an interesting endgame. Most spirits want to possess people to give themselves a foothold in the physical world. Their pure spirit forms are too weak to do more than leech off the living. But envy demons want to actually become mortal. They observe their target, usually someone of status, memorizing all their mannerisms. When they're able to perfectly imitate the person, they take on their form and dispose of the original. Of course, an envy demon is never satisfied and is always looking for someone more powerful to take.
Previously thought to be a variation of sloth demons, despair demons are actually something much more sinister. They are what's left when a spirit of hope is perverted and twisted out of recognition. Untarnished spirits of hope are some of the most powerful benevolent spirits that exist, though they're rarely seen in the physical world. The most dangerous despair demons can rival that power and use it for evil.
Some weaker demons simply infest places where despair is prevalent, like slums and prisons. But the more intelligent of them understand what causes despair and actively works to cause it among populations. They wear away at a person's sense of purpose, spreading their icy influence until they're so wracked by misery that they hurt themselves or others just to be free.
Some of the most deadly (and certainly the most fanservice-y) of demons are those of desire. But that doesn't just mean physical desire, despite what they might look like. It covers all the yearnings of their victims, including the desire for wealth or power. They're wickedly intelligent and know how to manipulate humans into getting what it wants, and some are even powerful enough to resort to outright mind control. They're the most skilled at tempting mages into possession. They'll try to bargain their way out of danger, but beware, their deals are more likely to work out for the demon than you.
By far the most dangerous and most intelligent of all the demons are the pride demons. They're corrupted out of wisdom spirits, or even powerful faith spirits. They're huge monstrosities immune to many of the abilities that usually harm demons, and can be extremely dangerous for your party.
Scholars in the Dragon Age world believe they're most dangerous because they are the most like humans: cunning, clever, with a penchant for cruelty. Unlike desire demons, who simply bribe mortals, pride demons corruption is more subtle. According to the in-game Codex, their influence can make "clever men outwit themselves, strong men crush themselves, and humble men forget themselves." They turn a mortal's best nature against them.