For He will give His angels charge over you, to guard you in all your ways. Psalm 91:11 NAS

God’s angels deliver messages to human beings, serve God, guard His throne, praise God, carry out the will of God, and protect humans from harm.Michael, Gabriel, Lucifer, Sera phim, and Cherubim are specifically named and described in the Bible.

Descriptions can be found in the following scriptures: Daniel 10:5-6, Daniel 8:15,
II Corinthians 11:14, Isaiah 6:2, and Ezekiel 10:21, respectively.

As for Lucifer/Satan, he and his fallen angels are deceivers, masqueraders of light, and instigators of some physical sickness, tempters, liars, and workers of evil happenings. However, one day that shall all end according to Revelation 20:10.