Magnus looked puzzled for a moment before realizing he meant Jack. "Not much, to say the least. I can sense it from him, I'm not as stupid as he thinks. He wants to kill me, destroy my empire or take ownership. Once he has served his purpose I will do away with him, all I need his a little more time. He thinks he is of top priority, but once he finishes his projects and I have access to his plans I will find someone more...loyal..to do what needs done." Magnus replied. He hadn't really trusted Jack from the start, atleast, not fully. He needed to give him the sense that he was of high importance and trusted for him to agree. He knew from the beginning he had it out for him, for wrecking what he cared most about in the world, the Terebitha. But, Jack presumed Magnus had no knowledge of what he was planning, but Jack was all to wrong. For, you see, Magnus isn't as simple minded as most vampires. He swiftly asses each and every possible outcome to a nearly flawless degree, everything Magnus does or everything that happens there's a good chance he already expected it in one outcome or another. 

Though, it's not always accurate, it brought him to where he was today with only minor hinderance. Magnus was already planning to eliminate Jack soon after he finished his projects, after he had a sufficient amount of his hallucinogenic produced for use. Yes, the second Jack outlived his usefullness would be the day he died.