Special guardian and protector of a mortal
A Guardian Angel is an angelic being assigned to protect and guide a particular person or group. The Guardian Angel often acts to protect a person from harm and ward off misfortune.
In certain special cases, the Guardian Angel does not have to be angelic by birth, but can become one by means of a mystical ritual, provided the Guardian Angel meets the criteria: first, she must be physically strong and resilient as well and generally of good breeding. Those who do not meet the physical requirements have no hope of becoming a Guardian Angel.
Secondly, she must have a connection with a Good power, preferably one devoted to protection, though the latter is not necessary.
Thirdly, she must have a ward who possesses magical powers and who has a 'special' magical nature beyond a human, elf or half-elf. For example, a Half-Celestial Elf, an Elpha or an Elf Paragon.