Difference between kremlin and gremlin according to google, keep in mind I have no animosity towards russia. Nor am I xenophobic against russians. I like using their words against them.

is that gremlin is a mythical creature reputed to be mechanically and mischievously inclined to damage or dismantle machinery while kremlin is (architecture|russian architecture) a fortified, central complex found in various russian cities.

From an etymological perspective or occult one, this is very interesting.