To Create Conflict Use Disguise and Deception
One the most important (and least discussed) ways to create drama in a story is by using disguise and deception.
Disguise and deception were central to much of the best plotted literature of the 19th century. Witness their importance to Les Misérables, Cyrano de Bergerac, The Scarlet Pimpernel, and A Tale of Two Cities.
In Les Misérables, arguably the greatest fiction work of that period or any period, crucial to its drama is Jean Valjean assuming a false identity and living in fear of his lie being uncovered by his nemesis, Inspector Javert. If Valjean’s disguise/deception is unmasked, he will be destroyed.
Another example of a film brilliantly using disguise and deception is The Mark of Zorro with Tyrone Power. In Mark of Zorro Don Diego Vega has three personas in his characterization: the strong (in private) Don Diego, the public foppish Diego, and the swashbuckling Zorro.
The protagonist having multiple, conflicting personas is integral to creating drama in the best-costumed hero stories. Take, for example, Clark Kent in the Superman stories. There is the real Clark, a strong and intelligent man mostly only experienced by himself and his parents. Then there is the Clark Kent public disguise, the mild-mannered reporter. And, of course, the public hero in suit and cape, Superman.
A similar three part personality also makes up the character Batman. Having three personas in one character is an important reason why Superman, Batman, and Zorro are amongst the most interesting and popular of the costumed heroes.
One character having three personas creates internal conflict in the character, dramatic and amusing irony for the audience, and difficult complications for the hero as he battles for justice in the world.