It's a normal angel, but it was thrown out of heaven. It had done something that wasn't allowed in heaven and god had gotten mad at them. The angel was given a choice. To go to hell or go down and live with humans. Every time the angels choose to live with the humans, like any angel would. Once the angel got down to earth though, they could not remember anything from heaven. They remember that they are angels but nothing else. It had be taken from them and they must live with that empty feeling in them for the rest of their human lives until they die. Some of the angels want so badly to remember their past lives and leave earth they start self harm, hoping to die and see heaven again. Most angels are given a second chance and are allowed back to heaven, it depends how big of the rule that had been broken was. A sad angel is kept on earth until the day they die. It is cruel but it is needed to teach the angel a lesson. After they die they are forced to spend two long days in hell before returning to heaven.

If wind comes out of the angel's mouth that means that they are annoyed, angry, or upset.
If wind swirls around their body they want to kill or harm you. An angel's words are painful and came harm the outside and the brain.
A human thing can hurt an angel, burning them into another death making them leek down into hell. It is the third choice if God wishes them to be sent away from heaven.