Novus weapon upgrade system findings

[Radacci]

There's no materia V listed under new items, that won't be the materia you need.

because it's already in game? just no convertible items in that lv range yet, to get it....well at least there's Carbonized V as quest reward. (duno about the ilv90 craftables, if they are convertible)
possibly you can get them by de-synth.