You missed a word:
known. As in
"Huh. There are four known Arkentools?" Which, combined with the demonstrated imperfections of Stupid Meal info and the Literary Axiom of
Checkov's Gun, in turn suggests (a) all four known Arkentools will be identified by the end of Chapter II and (b) tangible evidence of additional Arkentools will be given by the end of Chapter III.