Alignment is sometimes a general indicator of a character's Morality in the case of angels and Demons. Unlike Morality, it is a permanent choice and cannot be changed.
Mortals are not said to have any Alignment.
There are three Alignments:
When a mortal chooses to become one of the good Morality classes, they choose the Angelic Alignment. Angels powers' are tied to their actions, and they face losing them should their morality drop too low.
A character must be of good Morality in order to select a Class of Angelic Alignment.
The Neutral Classes are not aligned with the Angels or Demons and (generally) derive no power from their Morality; as such, it is free to fluctuate at will with few repercussions.
The Neutral character classes can be selected regardless of Morality and include the Sorcerer and Myrmidon.
Demonic characters are, like Angels, tied to their Morality; however, their powers are derived from evil, and should their Morality raise too high then they also lose access to their powers.
A character must be of evil Morality in order to select a Class of Demonic Alignment.