Joseph Smith (Mormonism) introduced a radical concept that included an explanation of angels:  All beings - God, devils, angels, humans, spirits... are all the same kind of being, just manifesting different stages of their existence.   This continuum even includes matter itself as a raw form of intelligence.  

As the narrative goes, God the Father organized "intelligence" into spirits in a process undescribed, but involving God the Mother, and the spirits produced are literal children of God.  All of these lived together in the celestial kindom of God the Father, and desired to progress, to learn and grow in glory and intelligence just as any child desires to be like their parent.  God gave the task to his children to present a plan.   Lucifer/Satan existed there as a spirit child and presented a plan of control to ensure none would be lost.  Jehova/Jesus was also there as a spirit child and proposed a plan of agency and risk with himself offering a saving sacrifice.  All the beings we call humans, spirits, devils, angels, and so forth were also there, all spirit children of God the Father.  The plan of Jesus was chosen, Lucifer rebelled and a third of the spirits followed him, eventually cast down to the earth itself, which was created as part of the plan. The evil spirits people encounter are part of this third cast down.  The other spirits who did not rebel entered the world through bodies and they interact with the spirit realm through a "veil of forgetfulness".  These interactions include angel visitations and ministrations. Some angels are spirits that have not yet received a body, some are spirits of those who have died but have not received a resurrected body, and others are immortal ressurected beings in the pattern of Jesus' ressurection. (The angel Gabriel in Mormon tradition was Noah when living on the Earth in mortal form.  Michael the archangel became Adam)  Eventually, as Joseph taught, all beings will be resurrected in the physical, with immortal bodies.  And if they so choose, they can become gods themselves, able to create worlds and produce spirit children just as their heavenly parents before them.  

Of course, this is a hard pill for a conventional Christian to swallow, largely because Christians emphasize how lowly the human state is compared to God, and God's eternal supremacy.  To become like God sounds blasphemous.   But on the other hand, there is a certain nobility to it, a quiet glory to knowing that every person we meet, no matter how lowly or terrible, has value that derives from their potential to realize the magesty of God personally.  It's also comforting to know angels not as some alien creature, but as a brother or a sister with familial concern for us.  

As an interesting side note, There is a relationship between this view and the view of Eastern religions that understand that each person can awaken to the realization that they are god, and so is everyone else.