Angevil is divided by 3 races: Humans, Angels and Demons. You will always start the game as a Good Human and in time you will decide wich side to follow.
Basically to turn into a Angel or a Demon you must have your Karma with the Good (blue) or Bad (red) alignment. You can see that in your Status window.
To increase or decrease your Karma value, you must fight specific players or monsters. Fighting a Bad (red named) player will give you positive Karma, fighting a Good (blue named) player, will give you negative Karma.
To turn into an Angel or a Demon, you must have your Karma value at 50 Positive or 50 Negative respectively and... die! =D (What do you expected?) If you turn into one of these, your Karma will return to 0 (Neutral).
Getting your Karma to positive while being a Demon or negative while being a Angel, will give you the chance to cross the human world and goes direct to the other side but, if you were an Angel and got 50 negative Karma, you may turn into a Fallen Angel (instead of an Demon) and go to Hell. For those Demons that got 50 positive Karma, they can choose to turn into Awaken Demons (instead of an Angel) and go to Heaven.
If you want to go back to Human world while being an Angel or an Demon, you must keep your Karma between -49 and 49 and... die! =D
Different Races will fight each other constantly and all of them share the same items, equipments and maps.

Anyway, this is the basic explanation of the Races that populate Angevil world so, choose wisely! ~~