Antagonist
Character Role Analysis
Waymarsh/Sarah/Mrs. Newsome
Yep, that's a trio of antagonists. They may not be Sauron trying to get the one ring or anything, but these folks ain't fun to be around.
First come, first served. At the very opening of our novel, the number-one thing we find out about Strether is that he's waiting at a hotel for his friend Waymarsh and half-hoping the guy won't show up. Which is a pretty good sign we're not about to like this guy. He's not the most evil in the world, but the dude's pretty solid as a frenemy and also a total Buzz Killington who seems bent on making sure that Strether doesn't enjoy himself too much while he's in Europe. It's only later that we realize Waymarsh is probably reporting back to Mrs. Newsome behind Strether's back.
Onto the next one. Mrs. Newsome is really the kingpin (queenpin?) of the antagonists in this book, since she holds both financial and emotional power over Strether. When Strether disobeys her, she sends her most powerful ambassador, Sarah Pocock, to track him down and make him explain himself.
And it looks like Mrs. Newsome has trained Sarah well in the subtle art of manipulating a man into cowed submission. Sarah refuses to let Strether know what she's thinking or what Mrs. Newsome has told her. This is because these crafty women know that Strether is an anxious person who will consume himself with paranoia if he doesn't know what someone is thinking.
By the end of the novel, Waymarsh and Sarah have become close allies and Waymarsh leaves Paris at Sarah's side, and everyone who understands fun heaves a sigh of relief. For lack of a better term, they're total party poopers who just can't stand the idea of other people enjoying life while they're so miserable. And that goes for their boss Mrs. Newsome, too.