Lan Fan is one of two bodyguards of Ling Yao and the granddaughter of Ling's other bodyguard, Fu. She is very quiet and cares deeply for Ling. As a result, she is constantly thinking of his safety and often forgets her own. Lan Fan is a very skilled fighter and is able to sense the presence of a soul (referred to as chi); thus she can quickly identify Homunculi like Envy that have more than one soul in their Philosopher's Stones (meaning she can easily see through Envy's disguises). Although we are never told her age Ling refers to her as a "girl" so we can assume that she and Ling are around the same age.

(Source: Wikipedia)