Demons:

The Greek terms do not have any connotations of evil or malevolence. In fact, εὐδαιμονία eudaimonia, (literally good-spiritedness) means happiness.

Demons, despite being typically associated with evil, are often shown to be under divine control, and not acting of their own devices.

Important Demons/Types:

Nephilim

ones who have fallen," equivalent grammatically to paqid "one who is appointed"

Belial

Hebrew adjective meaning "worthless"

Kabbalah

literally "receiving/tradition" 

Dæmons

Dæmons are the external physical manifestation of a person's 'inner-self' that takes the form of an animal. Dæmons have human intelligence, are capable of human speech—regardless of the form they take—and usually behave as though they are independent of their humans.

It is uncertain when or how a dæmon is "born" or into what form they are born. When a person dies, their dæmon fades away, like "atoms of smoke."

Although dæmons mimic the appearance and behaviour of the animals they resemble perfectly, dæmons are not true animals, and humans, other dæmons, and true animals are able to distinguish them on sight.

The Dæmons are based of Philip Pullmans' His Dark Materials, I loved the books and I was SO happy when I actually found The Amber SpyGlass in a bookstore...plus I bought Attack On Titan. HUEHUEUHE

Dæmons are digitally inserted though, because the future is wow. But you can still touch them and everything...just can't feed them. They are a part of you so the survive off you, but not like a parasite though.

Demons, however are heavanly beings. But they do blend in with Humans and do all the things Humans can. They look normal too, they don't look like crumply people and their final form is more or less exactly like the original one.