After a private conversation of searching from the "abysso" to demons we ended up with "what are the angels?" In the bible they are the ones being held responsible for the seven churches in the book of Revelations:
Unto the angel of the church of Ephesus write; These things saith he that holdeth the seven stars in his right hand, who walketh in the midst of the seven golden candlesticks;
So what and who are the angels?
The Greek word, aggelos which means, a messenger, envoy, one who is sent, an angel, a messenger from God
The Hebrew word, mal'ak which means, messenger, representative, the theophanic angel
Theophanic = (theophany) a visible (but not necessarily material) manifestation of a deity to a human person