Welcome to Humor Nation. Towards the end of Season 1, we were introduced to the demons. The first demon we heard of or seen was the yellow eyed demon was Azazel, responsible for the death of Mary, ultimately setting John on a path of revenge. Later on, we came across the ordinary demons such as Meg. Demons are a kind of entities which are evil and malevolent, completely opposite to angels who are good in nature. A demon is born from a human soul who has been tortured for a long time. Through the torment in hell, a soul ends up becoming something evil and distorted, ultimately a demon. A demon can move freely in the form of smoke, but to walk the earth, they need a vessel similar to the angels, they can also possess a human body. While an angel seeks permission from the human vessel.
We have never seen the true forms of the demon, we have either seen them in form of black smoke or seen them possessing the meat suits aka Humans. All the demons have the black smoke with the exception of the Crowley who has a red smoke because of him being the king of the crossroads. There are different kinds of demons, there’s a power hierarchy which has been made pretty evident in the show. Apart from the normal black eyed demons, we saw the first white-eyed demon in the form of Lilith, these are the oldest ones. They rank at the top and serve as the leader of the staff. The demons who work under them are extremely terrified of them. These demons can easily hold their ground against the angels, even defeat them with ease.
Then we have the yellow-eyed demons who are the princes of hell. The first yellow eyed demon we came across was Azazel. These demons are extremely strong and possess a variety of powers such as controlling fire, manipulating a human’s mind and project dreams. Azazel was tasked with the responsibility of freeing Lucifer from hell. Perhaps the most powerful ones in the demon hierarch are the Knights of Hell. Lucifer was the one who handpicked these demons and they were trained by Cain.
Interestingly, how demons were once the dreaded enemies of the Winchesters and the angels, but fast forward to Season 12, an angel and demon together are solving crimes, and assisting the Winchester.