Demonized angels basically,
"Her wings are broken
But I still find her beautiful
Her face is scarred But I still see the divine
While her own kind now calls her an outcast
I will make her feel at home
But before I focus on her healing, I must first pay a visit
To those same angels who made her life a living hell"
^Taken from a comment section somewhere that inspired me to write this damn page already fklglödfss
Fallen angels, are just infected angels. Their personality gets flipped upside down and they turn into a demon. They have a chance of recovery, if they believe they can recover. If an angel loses hope, they lose to the demons's infection, beyond return.
If an angel has a chance, only water-based elemental angels can make them return to normal after extensive care.
The restoring process is done via gems, that absorb all the corruption and evil energy, stuck in the demons's blood, that gets cleansed eventually by the gem. Often times, if a demonized-angel becomes aggressive, they get locked into a water-dome, they cannot touch, as it'll be freezing cold, stunning them, aswell as water reflecting light on its surface immediately.
An angel can be freed of infection when occuring ON-EARTH ONLY, if a loved one embraces them in a comforting way. Infected angels tend to soften down to their infected core, until their emotions eat it back inside-out, fading. There is no guaranteed chance of immediate nor regressive recovery, yet it is possible to some.
(Examples of a fallen angel; Mary )