"Context. I need to know more about how magic works, especially anything you know about what she can do."

Magic works a bunch of different ways based on what spells someone has. He's heard about the woman, Sakir, and thinks she can puppet bodies to control their movements or senses. Probably no more than one at a time for complicated things, and it should only rarely work on a champion. 

"Rarely meaning what, a failure chance, a high mana cost...?"

"Really high mana cost if she didn't want to be noticed - would be basically impossible if she didn't get a boost from being a summoner."

"And what do you know about magical contracts?"

"Pretty straightforward - you can't actually sign one if you don't understand the terms. They're a specific sort of spell - I think one of the other summoners knew how to do them."

"What if the participants understand the terms differently? What conditions have to be in place for a signature to be binding?"

"Signature won't take to paper. What do you mean about what conditions? I think it's just that both parties need to be alive, unless it says otherwise then it might just be the person doing the spell."

"Alive, have to sign in person... nothing else? Do the signatures have to be close together in time?"

"I think it costs the caster mana continuously if they aren't, but not an unreasonable amount for at least a few hours."

"Can I sign for things on behalf of my champion, is she bound through me?"

"You can sign for her - I don't think she can sign for herself."

"Do you know who Sakir's champion is or what they can do?"

"No idea."

"Anything else that seems like it might be useful for me to know?"

"Sakir has been around for a while and I'm pretty sure entered the tournament out of boredom. She occasionally keeps people as pets and I believe her treatment of them varies wildly."

"Does she have any pets now, do you know? Varies wildly in what ways?"

"I don't know of any current ones - I believe some pets ended up better off and friends with her and some ended up tortured to death."

"Do you know if she has any mind control or just body control?"

"I would expect mind control would have to be separate, but I wouldn't rule out her having something she can use on her captives."

"What would be the general possible range of the something if she had it, I basically don't know what this magic system can and can't do at all."

"I'd guess something she needed someone helpless to do? Otherwise I'd have hard rumors about it being used offensively probably. Probably also isn't permanent given that but I can't be sure."

"Does she have allies or friends who might be relevant besides her mystery champion?"

"I don't think so."

"Why aren't her ex-pets relevant?"