Character Analysis
Sir What Now?
Who is that masked man? In a little throwaway line, Walter reveals that Sir Percival really isn't really Sir Percival after all:
For her sake I wished to conceal it—for her sake, still, I tell this story under feigned names. (3.1.1.14)
See, Sir Percival was illegitimate: his parents weren't married when he was born. This was a huge deal in the Victorian era, especially when it came to inheriting property. Basically, illegitimate kids couldn't inherit property or a title. So Sir Percival is a big ol' fraud.
Sir Percival's big secret ties in nicely to the novel's themes of identity and lying. (Good job being relevant, Sir Percival.) But really, his "secret" was something of a shock and even a letdown. Walter was thinking the secret was a more exciting crime, like fathering Anne Catherick or even offing someone. Given Sir Percival's atrocious behavior to his wife, we aren't surprised that Walter assumed the worst.
Bad Behavior
The bad behavior to Laura is the other defining aspect of Sir Percival's character. He's basically an abusive nut who is sometimes physically violent and often displays a very nasty temper. He's the most obvious villain in the novel. Even animals recognize his evil nature:
The little beast, cowardly and cross-grained as pet-dogs usually are, looked up at him sharply, shrank away from his outstretched hand, whined, shivered, and hid itself under a sofa. (1.2.1.27)
It's notable that Sir Percival never gets to tell his own story. In a way, the novel distances us from him, helping preserve his status as the book's #1 Most Evil Villain. He's a mysterious force for bad, and the fact that he doesn't seem to be more that a foul-tempered, dog-repelling, evil-making machine makes him mysterious and sinister.
And his lack of a narrative voice also ties Sir Percival to his long-suffering wife, Laura. In his own way Sir Percival is as passive as Laura is. Granted, he has a violent temper, but his strings are being pulled largely by Fosco.
Percival rarely seems to think on his own, and when he does he tends to do really stupid things like locking himself inside a burning church. Not a good move, Percy.