Wallace is usually the cause behind Katie's crazy adventures, often misunderstanding circumstances, or agreeing to grant a dumb wish. He will sometimes cause Katie to realize what has to be done to reverse a wish, but this does not happen often. He keeps a diary, which has all of his deepest, darkest secrets, including the fact that he is afraid of the hunt. He is often the subject of magic from Emily, who usually does something to him to shut him up, including zipping his mouth, and then encasing him in vanadium.
However in the Pilot, he is very intelligent (Emily is medium intelligent) and he somewhat makes katie's wish very dangerous, when he said "I got to get this thing fixed", he was originally going to do it, but he doesn't have time.
He delights in creating elaborate contraptions that often do not work as intended. He is a self-proclaimed genius, evident from his exclamation when he discovers Hutch's borrowed skill, a talent for all things mechanical. Most of Wallace's inventions look not unlike the designs of Heath Robinson and Rube Goldberg; Emily revealed that she has said of Wallace that all his inventions are designed around the principle of "using a sledgehammer to crack a nut". He is also very eccentric and funny, and is always willing to provide a good laugh or listen to one himself.
He wears a red tie, a green jumper, Brown pants, black shoes, bald head and and a white T-Shirt. He usually wears his form and he doesn't have a crown and wings because his not a fairie but he is still Katie's God father.