Lord Utherin following the capture of Dragonstone by House Targaryan would become a prisoner in the highest peak of Dragonstone where he had a single window to look out. In this way he came to become an advisor to the Targaryan's in the hope that his loyalty would make them want to let him go. As time went by he found they never even got close to letting him go, and this culminated in Lord Utherin jumping from the window to his death hundreds of feet down.
Fall of Dragonstone
Main Article : Dragonstone
When Aryes Targaryan III. saw the mountain of Dragonstone he immediatly knew that this was the spot that House Targaryan would stop. Aryes led the caravan up what they discovered was a mountain trail. As they moved up farther they discovered a series of small temples and shines to gods they had never seen before.
After hours of marching up the trail the caravan was grreted with the site of a massive stone wall blocking their route. As they moved towards it they were greeted by three elves of clear dark elven appearance. As Aryes looked around and saw the ruins of other caravans, skeletons he immediately realized they were in some serious trouble. The elves bid they come inside their camp, and Aryes knew he had to think quick about how they were going t survive this, so he agreed to enter but he also spread word amongst his house that they were to prepare for battle, and when he gave the command they would attack the elves before the elves attacked them.
House Targaryan takes control
With the defeat of the Dark Eles the members of House Targaryan alongside their loyalists were in complete command of the fortress of Dragonstone. As they eplored the fortress they were shocked to discoer how truly ast the fortress was. The few Dark Eles that they had captured still refused to talk so they had to assume that the ast size of the fortress was due to the fact that they had captured the fortress from someone elce, and then maintained it through the use of the hundreds of slaes that they discoered as they traversed the fortress. It appeared that the Dark Eles had also been using these slaves to build a giant enclave within the largest of the mountains peaks which stretched miles into the sky, and was the tallest thing that Aryes Targaryan III. had eer seen in his life.
"'When I looked at the giant entrance to this fortress I was more then shocked at the scope of it. Judging by the slaves bodies that lay strewn about the ground it may have been a scary amount of time that they had been constructing their vision of a home. It got more amazing as we traelled up the giant stair cases and discoered that at different levels they had constructed these giant floors that in some cases stretched to be the size of individual castles."
-Aryes Targaryan III.
With the discovery that they had uncovered a place more Vast then anything they could have ever imagined they begin to clear out the fortress of the thousands of dead bodies that lay throughout it, as well as feeding the hundreds of surviving members of the slaves that had toiled for the Dark Elves over the course of the years they had lived there. As they got to uncover more information from the Dark Elves they discovered that the Dark Elves had been massivly constructing things throughout Dragonstone, and that underground their were also vast caverns which houses the slaves during the days they were not being worked to near death. The few suriving Dark Elves were placed inside of cages where they remain to this day with the survivors being Lord Utherin, Braelex and several other surivors of less importance. This couldn't have gone any better for the members of House Targaryan as they had basically inherited a nearly completely constructed capital city. As the fortress was fixed up they begin to set about the way in which it would look in the future.