Is it possible and can you make a Nostale client, which just opens inject the DLL called fileDLL.dll into your Nostale folder?
With multiclient, it would be ideal :P
Proxy any system DLL the game loads from the game folder, such as the Direct3D (d3d9 in this case) module. The load order will cause your module to be used first. Restore the original exports with simple jumps to before and you are in with minimal effort. No renaming of files or altering originals either.