I found this earlier thread on this board here about Makai:
http://www.behindthename.com/bb/arcview.php?id=374254&board=gen
The name does not sound Russian to me.
The "Think Baby Names" website which in my opinion is one of the better "Baby Names" sites thinks Makai is a form of
Michael. Well, why not, but hard to tell without further information backing this up:
http://www.thinkbabynames.com/meaning/1/Makai
Rene www.AboutNames.ch