To be able to say that x must be a certain way you need a truth value for x assigned to every given property (such that necessity is extensive with every property instance), which further entails quantifying over properties in the problem space so that x is given a truth value for for every property that may also not have x as function; in effect, for every given property, x either is a member across the distribution of the property, or a monadological property of properties it is not a property of. Ultimately, formulations of the form x is necessarily an F or x is necessarily not a G require universal quantification of the variable such that for every property F or G, x is distributed across properties of which it is and is not a member, such that it's necessity is supported by counterfactual truth (if x wasn't an F, it would be a non-G). This requires quantification over types of properties, meaning modal logic is necessarily second order at minimum.