Angels are certainly mentioned in the Bible, but demons are not referred to as "demons" (Revelation 12:7).
I'm sure that I will add more information on this subject as I learn more, but to give you some basic information, I have found the following:
There were probably two Archangels at the beginning of time. One was Lucifer and the other is Michael. Lucifer is the fallen archangel that is also known by many names - including Satan.
I noted that Cherubim is plural, thus one of these beings is a cherub (Ezekiel 41:18). Based on that, probably a single Seraphim is a seraph.
Since typing these references for you, I have realized that it may be a little confusing. The long description in Ezekiel 10 is describing a real living being, whereas some of the other references refer to the mercy seat of the ark of the covenant; which represent the cherubim, but are just parts of a structure; not the living beings.