WARNING: The following contains spoilers for Dragon Goes House-Hunting, Episode 9, “A Home for a Black Dragon”, now streaming on Funimation.
So far in Dragon Goes House-Hunting, Dearia has had three flashbacks, each covering a different part of his past. The most fascinating of these, however, is definitely Episode 9's, which features both the Black Dragon and a very different Dearia. The Black Dragon has been teased many times in previous episodes whenever Dearia’s old acquaintances run into him, so anticipation for his official appearance has been quite high.
The Black Dragon, Varney, sought out Dearia after hearing about the Dark Lord. Varney needed help finding a home, but Dearia hadn’t started his real estate business yet, and was still apprenticing under the Jormungandr, so he didn’t want anything to do with Varney. But the Jormungandr saw this as an opportunity for Dearia to explore the world and asks Varney to take Dearia on a journey, so Dearia reluctantly agrees to go.
Varney’s brashness, arrogance and carefree personality is the complete opposite of Letty's. He also has all the powers a dragon is supposed to have, including fire-breathing and flight. Though, like Letty, Varney also has a frightening reputation as the “Mighty Dark Dragon,” but he enjoys his infamy and even goes out of his way to satisfy people’s expectations of him by destroying fortresses and hiding in dungeons to mess with Heroes.
Varney’s first house-hunting stop with Dearia is at a Hero’s Guild, the door of which he destroys with just one knock. The Heroes in the guild team up but are no match for Varney. An annoyed Dearia also fights in an attempt to finish the battle quicker so that Varney can move in, but he ended up in a competition with the dragon to see who could destroy the most Heroes.
At this point, Dearia hadn’t yet developed his dry sense of humor, so he is easily annoyed by Varney’s antics and just wants to get the house-hunting over with. But to his surprise, Varney doesn’t really want the Hero’s Guild -- it's too fragile for him. This becomes Varney’s excuse for continuing to visit various human castles and “test out” different building materials. Their adventures drew the attention of the human world, now everyone knows about the Dark Lord traveling with the Mighty Dark Dragon and leaving on ruins behind.
During their travels, Dearia started to accumulate knowledge about building materials and architecture, thus it soon became clear to him that houses built for humans couldn't actually withstand Varney’s powers. Varney knew this too, but he didn't want to take houses away from non-humans, feeling it’s immoral.
As a powerful non-human creature, Varney believes that it’s his duty to protect the smaller creatures by drawing all of the Heroes' attention towards him, so although it appeared like he was only destroying things for fun, it was actually for a noble reason. And when he saw a new castle being built around a forest where many small creatures lived, Varney decided to destroy the castle so they wouldn't have to live in fear.
Dearia didn’t understand Varney’s actions at first, but he slowly realizes that his journey with Varney had taught him more about the real world than he ever would from simply reading books. And he finally asks Varney why he wants to find a house, and Varney embarrassingly admits that he wants a family, but female dragons won’t marry someone without a turf. The reason why he asked for Dearia’s help is that he wants to pass on his mantle to the Dark Lord after he’s married. So their 100-year journey of house-hunting continues.
There had been some speculation that Varney is actually Letty’s father, but Episode 9 shows that this is not true. First of all, they are two different species of dragon. And secondly, Letty didn't know Varney’s story until Dearia told him, so they couldn’t be related. But, even though on paper they are complete opposites, deep down, Varney and Letty both just want to live in peace with their families, and this is perhaps why Dearia is compelled to help Letty.