Manny is proven to be one of the worst antagonists in the Diary of a Wimpy Kid book series. He was the main antagonist of Cabin Fever, as he almost froze his whole family by killing the power to all rooms in the house except his own while there was a blizzard, which he claimed was because nobody taught him how to tie his shoe laces.
In the series
Manny is initially portrayed simply as a spoiled child, always getting what he wants and asking his parents for ridiculous requests and throwing temper tantrums when he doesn't get his way. He is never punished for his bad behavior and tantrums, despite common sense indicating that he should be.
His parents would give him privileges that neither his older brothers, Greg and Rodrick, received at Manny's age, such as he was allowed to bring toys into church. He has also shown an inability to stay at one preschool.
The book series shows the extent of Manny's selfishness, it is shown that he knows (or more likely guessed) Greg's computer password to get access, then spent all of Greg's points and coins in the game and then changed the password to make it impossible for Greg to access his game. He later does the same to the family's TV set by figuring out and changing its parental control, only allowing his favorite shows (all of them age-appropriate cartoons and educational shows like Sesame Street) to air on their TV while locking out access to all other shows.
In Cabin Fever, on Christmas Eve, once Manny hears of a coming blizzard and decided it was every man for himself, he stole much of the family's food and conveniences and shuts down all the power in the house except for his room so he can remain pampered, leading the others into thinking the storm blew the power out. While Greg's father Frank was staying at a hotel because of the blizzard, Greg, Rodrick and their mother were freezing in their house, in fear of starvation. They would have been dead had it not been for a passing visit from Greg's friend Rowley, from whom Greg finds out that none of the power was blown out from the blizzard. Greg checks the power circuit and finds out about Manny's plan. Greg and his mother confront Manny, who makes up the excuse that he did it because no one taught him to tie his shoes. The next day, Mrs. Heffley teaches Manny but as usual, she doesn't even punish him.
In The Third Wheel, it was explained he is scared of kids his age and has imaginary friends other then any real one. He also shows more of his selfish side when he locks himself inside a dog exercise pen with all toys present to keep any other kids his age from playing with the toys.
- Out of all the antagonists in the series, Manny is the only one who tries to kill someone, although this wasn't intentional.
- Manny will probably never grow up and stay a spoiled little brat for his entire life.
- He is approximately 3'1 and 30 lbs.
- He is quite similar to Stewie Griffin as both of them are the youngest of three siblings, very young in age, get away with a lot of things they shouldn't, and are rather smart and manipulative.