Elena Potato

Elena moves with her parents at Oldmill Village. When she gets there, she befriended Zick, a loner who has allergies and on the top of that, can see monsters that are invisible to the normal people. Not only she is Zick’s friend, but also neighbor.
 
Since then, Elena is aiding Zick through his adventures, although she can’t see monsters. When Elena is so sad about being useless, that’s when Greta, Zick’s mother, grants her the Gift of Sight, the ability to see monsters. That’s how Elena is now useful through the entire series.