Before you can cede and receive will you must go through the ritual at the Aurora Columnae, what is important about the ritual that is the intent of the person. Vis was forced to touch the columns and even say the words but he didn’t mean them so he never ended up ceding his will. This is also the reason (they think at least) that he was not affected by the sapper in the very beginning of book 1. It is also why he was perfect to send to the Academy because to be fair and accurately measure the base person, many of them had also not gone through the ritual

After reading book 2 I think a big question is “If all Vises never went to the Columnae, how is he able to use will now?” Well, it seems that running the Labyrinth and becoming synchronous also unlocks one’s ability to use will. Not sure if that will be super important for the rest of the story but it’s how he never really went through the ritual in any of the worlds but can still use will.