This is part of the "shackled" world series.

Recently a wealthy aristocrat passed away and his belongings were seized by the government who immediately began to auction them off. However one piece of his property was too much for any of the auction goers. After several attempts to auction off this titan of a beast, they eventually moved to more sneaky tactics to earn something from him. After posting an ad for a beast that needed to go, free shipping available, it was seemingly too good for you to pass up. Now you have a behemoth to take care of, one who may take you out if he ever realizes he was capable of such.