Scarecrows are among the most common form of Rouge Demons. Scarecrows normally spawn from those who choose the path of a Demon while they are near death, in order to save themselves with Immortality.
Even so, their morality and mind die so that they are mindless demons that attack and can only be manipulated through the sin they commited to be created, which in this case is Greed.
Scarecrows are unnative Demons who spawn from the Greed of Humans who desire to gain immortal life. These Demons can only be created from those near death and therefore have a weak body and mind which causes them to loose control of their sanity, making them into Rouge Demons.
Scarecrow's bodies have deterriorated and mutated into a much weaker form then their normal skin, which is the price they pay for immortality.Their bodies must be stiched with strong clothes granted to them by their overlord; Greed. This gives them their scarecrow like appearance and their name. Their bodies are also stiched to weapons that they use to fight, mostly long blades.