Charisma vs Manipulation

Last night I pulled a nasty one on my players.
Way back in the first session of my Scion campaign they'd spared the life of an NPC villain. I'm a sucker for a redemption story, so allowed their good roleplaying and hot dice to turn this person. She is no longer a minor luitenant in the badguys army, she's instead been the PC's sidekick ever since. She's been in every session, traveled cross-country with them, and fought at their side. Tons of personality, a vital and prominent part of the game.

The PCs have some pretty solid powers to detect lies and deception. They've known her loyalty to them is genuine, earned when they helped her crawl out of the gutter and put her life back together. But they've also had reason to believe she'd occasionally held back info about the level of her involvement in the big bad's activities. Last night it came to a head. They needed info. She was dodging the question. So they tried talking it out of her. As is typical to persuasion attempts in my campaigns, I let players role-play a little, then make them break out the dice. The dice supplement the roleplay, and the value of arguments they made in-character translates to extra dice. This being Scion, the PCs rarely have bad rolls. Epic attributes generate tons of automatic successes, and they can throw stunts, virtues, legend, etc at any die roll that really matters.

So I said "Depending on how you go about this, that can be either a Charisma+Empathy roll, or a Manipulation+Command roll". The players took a quick look at their character sheets. Not a single point of Empathy in the whole group. Of course, I already knew that. This had been a set up months in the making.

They chose to roll Manipulation, and after thowing everything they've got at her, score an amazing 22 successes! Tears running down her cheeks, she confesses everything, and gives them all the dirt on the bad guys.

Rest of the session plays out great. Armed with her dirt, the PCs stick it to the big bad. Story's far from over, but they've definitely gone on the offensive and really hurt the villains.

End of the session they get home and find that their NPC sidekick has run away. "And since I know how much it sucks to wonder where you went wrong," I say to the players, "I'll let you know. If you'd rolled Charisma+Empathy, she would still be your friend."