As I walked back from the research building to my room, I had a smile on my face and I was tired.
The reason for my smile was that Ulka had accepted my proposal. I had made a mana contract with him after he had accepted my offer to remove all his doubts, and he had agreed without much question to do a detailed investigation into the Tenebra family. With my answer of 'family matters' and the assurance of the contract, he didn't press me.
As for my exhaustion... I have to pretend to be a mysterious person in Ulka's eyes, that's the only way I can use him. He has to believe that I'm not a normal person, that I have secrets I can't reveal, and that I'm very influential behind the scenes, even if I don't look like it on the outside.
Otherwise, even if there's a contract between us, he'll believe that I'm someone who just makes things up, and there are a few other reasons.