Pinion

Pinion is the 8 year old younger brother of Rose. Later in the series, once Rose finally meets up with him again, it is found out that Pinion actually has the unique ability to be able to remember anything he sees and be able to map it out. For example, if he walks through the hallways of a castle he'll be able to draw it out. Because of this, some researchers take him from their aunt and uncle who 'gave them their permission' to take him and they want to use him for his unique ability to be able to find the weak points of their enemies castle.