Modern Dragon Knight

My cat can talk, and there’s an elf beauty of idol caliber at home. A thief is my assistant, and the guard at the door is a wind dragon. One day, a distinguished guest came to my home. Pointing proudly at a picture, he said, “When you buy something, you have to choose carefully. I’ve made my choice, so let’s buy this and take it home!” I took one look and suppressed the urge to beat him up. “Your Excellency, this is an American Nimitz-class aircraft carrier. Even if you wanted to buy one, they wouldn’t sell it to you! And you don’t have anywhere to put it!” “They won’t sell it?” The guest rubbed his chin. “Then I’ll take this one!” “That’s a space shuttle. It’d be useless even if you bought it!” “This one?” “That’s a nuclear bomb. No one would dare sell you one...!” “This one...!” “That’s the Bismarck battleship. It already sank!” “Then what exactly can I buy?”