Finn Michael Greystone is the youngest of the three Greystone children. He is the Other World's version of Finn Gustano. Finn is very wild, imaginative and impulsive. He can often be scatter-brained, with his thoughts flitting from one place to another and leading him to forget things. He is very energetic, mischievous, and incredibly daring, and gets confused when older children and adults are more careful and fearful.
He is very attached to his family, especially his mom, Kate Greystone; when she leaves on business trips, he gets very upset and often cries when considering it or other unpleasant things. He is also very close with their pet cat, Rocket, and pets him when stressed.
His most dangerous vice is his impulsivity and inability to think before speaking, which causes him to blurt out information that should have been hidden, put his feelings on display for all to see, and sometimes draw unwanted attention, such as when his outburst at his mother's trial almost got them caught and arrested. He is noted to be a good actor when the situation calls for it, though, and he ends up close friends with Natalie Mayhew, as the two of them usually worked together to deceive her mother into believing nothing was wrong.
Finn also gets upset when he is treated as a child and unable to understand things by his siblings, and insists on being told the same things as them.
