When does shes manipulate anyone?
Elspeth convinces Viridiana to tell her about he main characters past, and learns that he used to enjoy getting into fights for fun. She also learns that those fights were what caused the main character and Viridiana's brother to become close friends. A short while later, Elspeth sees the main character trying to avoid a fight with two drunks at the beach.
Elspeth is supposed to be a pacifist, so she should be wanting to avoid a fight. Elspeth is supposed to be highly intelligent, so she should be able to avoid the fight. Elpseth has extensive military training and experience, so should be able to easily handle a small drunk. And yet... what happens? Elspeth interjects herself into the confrontation and gets a bloody nose.
There are two possibilities here. One is that Elspeth is the worst written character in the game, one whose actions contradict everything about her established character. The other is that she started the fight intentionally and let herself get hit to garner sympathy with the main character and get closer to him.
When the main character takes Elspeth aside to check her nose and tend to her wounds, she takes her pants off in an obvious attempt to seduce him. It should also be noted that Elspeth had tried to get the main character drunk during during a drinking game earlier that night in which she was only drinking tonic water. So trying to seduce him here and now is not only manipulative, but super skeezy. When you avoid the kiss, she puts her pants back on and leaves (without losing her legs).
You can reasonably conclude that Elspeth intentionally provoked that guy into attacking her, and let him hit her to get closer to the main character. The game has constantly insisted that Elspeth is a super genius and skilled at manipulating people. So surely she could think of a way to talk two drunk guys out of attacking a world famous professional fighter. Or at the very least, not be stupid enough to think that turning into a live action version of the navy seals copypasta would do anything other than get an angry drunk guy to swing at her for insulting him.
She is also portrayed to be a well trained fighter with military experience. So avoiding a predictable punch from a drunk should be reasonably easy for her. And yet she fails to do that. However, she doesn't get her nose broken, just bloody. So she's either lucky, or she rolled with the punch just enough to get a minor injury that would require attention and garner sympathy from the main character.
Elspeth is also supposed to be a pacifist. So her getting into a fight should be seen as unusual. Which it is by the main character. He asks her why she did it, and she says "My friend was in danger, I did what I had to do. My personal view are irrelevant." He thanks her for her help, and she says "we're officially brothers in arms now." And then she leans in for a kiss. While pantsless. Knowing that he's been drinking that evening.
All of that fits perfectly with the idea that she has been trying to create a scenario where she can get closer to the main character by using what she's learned about him from those who truly know and care about him. If this seems like a stretch, you just have to remember that we've already seen her be manipulative on other occasions.
If you try to avoid eavesdropping on Elspeth's first conversation with Viridiana, she will motion you back because she wants you to see how smart and helpful she is. And she gets visibly angry with you if you ruin her plans by interrupting her. She also tries to keep you from getting together with Katie by saying that it would be unprofessional, but it would seem that her rule doesn't apply to Elspeth herself as she constantly throws herself at you. We've seen her "accidentally" leave her purse behind on her trip to the bathroom while we are meeting her father, only to see that she did it on purpose in order to secretly record our private conversation.
Elspeth is manipulative. It's been well established on several occasions.