Magnatum coin is completely independent of signatum.
It has its own unique feature, and a lot of work has been done to add it into source code and to get it to work correctly. If you are able to read the source code you easily can see it.
As the magnatum uses the Skunkhash Raptor algo it's obvious that the easiest way to gain it was to fork signatum and use its wallet sources. The same about the website template. But It's only the beginning of the work.
And as you can see the developers are from Russia (I'm not the one) so they cannot be that guy whom you're talking about.