AFAIK, in short:
Elmax and Vanax are from Uddeholm (now owned by Bohler).
it's a sharp edge steel retaining many of "hard carbon steel" properties while being stainless, thanks to fine carbides.
* good stain resistance
* gets pretty hard
* good edge retention
* fairly easy to sharpen
* more on the hard/brittle side
Nitrogen steel: extremely stainless (for salt water use), mechanical properties compare with Elmax except doesn't get as hard, probably similar to X15-TN.
Niolox is from Lohmann steel using Niobium chemical element:
* regarding mechanical properties similar to D2, somewhat longer edge retention, somewhat tougher