This particular Domovoy used to be a spirit guarding an ordinary family home, but when his brethren ended up imprisoned in the colossal factories he decided to lead a revolution to free all the Domovoy from slavery.
The Che Domovoy Minipet DLC unlocks the Che Domovoy rare minipet (+5% Magic item find bonus, +10% Gold find bonus), a friendly monster that you can't get rid of. You will also receive a rare item: The Mephiston Helmet.