Nicholas is a very smart young man who has planned out this day very carefully. He is dying to get into that lumber room. There is nothing worse than being told you cannot go into a room. He knows his aunt well, and he knows if he puts the frog in his bread and milk in the morning, she will arrange for the other kids to go someplace fun. Then he will have the house to himself.
He is a planner. He knows where the key is hidden, knows how he is going to it down from the shelf, and knows how to open the door since he practiced on the schoolroom door. When he opens that door, he has a wonderful experience because he is very imaginative. While looking at the tapestry, he creates a whole scenario of what is happening in the picture.
“But did the huntsman see, what Nicholas saw, that four galloping wolves were coming in his direction through the wood?...... would the man and his dogs be able to cope with the four wolves if they made an attack?” (pg 4)
Later we see that he is a quick-thinker. When the aunt becomes trapped in the rainwater tank, she calls to him for help. She promises to give him strawberry jam for tea, although she has no intention of doing so. Nicholas knows that. Nicholas says that he thinks she is the Evil One tempting him to disobey. He will not give into the temptation. He uses the subject of the strawberry jam to convince her that she must be the Evil one. So he leaves her there in the rainwater tank until the kitchenmaid rescues her.
He has a sense of humor. The reader finds himself smiling at Nicolas’s ingenuity. He has a spirited sense of fun, which I don’t think the aunt appreciated.