Don Paolo

"Layton has been my archnemesis ever since that fateful day!"

- Don Paolo about his grudge against the Professor

Don Paolo is the primary antagonist of the Professor Layton series of videogames in the first trilogy (while Jean Descole is the primary antagonist of the second trilogy). In the first game he acts as the main antagonist, in the second game as the secondary antagonist and appears as a supporting hero in the third game. In the movie however, he only has a minor appearance.

Personality
Don Paolo considers himself Layton's archrival, a claim supported by the fact he is considered a criminal mastermind within his own setting and was a scientist of the highest nature. He is also a master of disguise.

Powers and Abilities
Don Paolo has the admirable ability to disguise himself as absolutely everyone, even people much thinner or smaller than himself. He is furthermore able to completely copy their personality, voice and even the way they move, making it almost impossible to expose him.

Being a scientific genius, he is very talented at inventing and building all sorts of useful and dangerous contraptions, especially flying machines. These are often concealed, for example as umbrellas or cars. He is also an escape artist, being able to flee from the police at every single one of his appearances.

Backstory
At his time at the university, he was in love with Layton's girlfriend, Claire. After working as a scientist, he was expelled from his position due to his unethical nature.

The Curious Village
Wanting to find the treasure of the Reinhold family Layton was searching for, Don Paolo would become the main villain of Professor Layton and the Curious Village where his profile gives a rather unique insight into his personality as it notes that when not committing evil deeds Paolo is fond of listening to music. Furthermore he disguised himself as Inspector Chelmey to frame Layton in a murder case with forged evidence.

The Diabolical Box
In Professor Layton and the Diabolical Box Don Paolo shows his skill of disguise by successfully managing to play the part of Flora - being able to fool many into believing he was her, according to the profile he was so good at this he was even able to mimic her walk. Disguised as Flora, he wanted to solve the mystery of Anthony Herzens Elysian Box he had stolen from Laytons's mentor Dr. Andrew Schrader.

The Eternal Diva
Don Paolo was briefly seen in the beginning of the movie Professor Layton and the Eternal Diva, where one of his plans was foiled by Professor Layton on the Tower Bridge.

The Unwound Future
It is also revealed that Don Paolo's rivalry with Layton stems from the fact his love, Claire, was in a relationship with Layton - this embittered Paolo towards Layton and he swore revenge: An oath he seems to live by until he teams up with Layton in Professor Layton and the Unwound Future to solve the mystery of future London and stop Dimitri Allen. After furthermore helping to save London from Clive, Don Paolo watches Layton's success from an rooftop and presumably flees afterwards.

Manga
In the manga series Professor Layton and the Cheerful Mystery, where Don Paolo acts as the Big Bad, he is depicted as an incompetent On & Off villain and a Scapegoat, rather than an actual threat:

He appears in almost every story, often building machines like giant robots (which always halve a self-destruction button) to threaten Layton and Luke, however, in some cases he helps them, sometimes even to stop his own doings (For example after creating a killer robot or when he ate one of his own poisoned mushrooms and mutated, so that Luke had to find the antitode). In general however, he doesn't redeem himself completely, like he does in the games.

A recurring joke is that Layton tends to forget about him.

Quotes
"Layton! You! You will pay for this someday! I won't forget this!"

- Paul

"Here I come! Ready or not!"

- Don Paolo

"It isn't over yet, Layton! Just you wait! One day I will have my revenge on you!"

- Don Paolo, after his defeat

"Nyeh heh heh! Well played, Layton! I'm sure you're very proud of yourself for seeing through my disguise again."

- Don Paolo at his return

"Layton, you'll pay for this!"

- Don Paolo in the movie

"What?! Don't act so surprised! I have... feelings too, you know!"

- Don Paolo, after Luke found out about Claire

"Ugh. Spare me your sappy sympathy. And my name is Don Paolo. Address me as such, boy!"

- Don Paolo to Luke

Trivia

 * Don Paolo has a cameo appearance in one of the Weekly Puzzles in Professor Layton and the Last Specter.