So, I was doing a quest in the main questline, and it took me to blackreach, which is a really cool dwarven ruin. I look off into the distance to see some sort of dwarven fort, with falmer patrolling around it. The fort had this huge orb floating in the middle too. I shouted at the falmer from a distance, it knocked them down and hit the orb in the process. I then make my way to the fort and I see a ancient dragon named Vulthuryol fly out of nowhere near the fort. Instead of flying, he crawled the whole time in the battle. I simply used my companions as meatshields and stun locked him with fireballs to defeat him. My question is, how did he end up here? In a dwarven ruin.
I think that he had to hide during the Akaviri crusade to Tamriel which started in Skyrim. And the reason he is crawling is because he has been sleeping and not flying in Blackreach (the low ceiling) so when you awaken him (by shouting at the orb which makes a big clinging noice. Thats what i think.
I can only think of 2 ways that he would be down there.
He could have been captured by the Dwemer, they had the technology after all, not to mention access to the heart of a god.
The entrance that he used to get in could have been blocked off, trapping him inside.
I'm voting for the Dwemer one as it seems more likely.