Black Wing, Blue Wing

A How to Train Your Dragon x Fourth Wing Fanfic...
When Astrid joins the Riders Quadrant at Basgiath War College, she knows better than to die. She's fast, ruthless, and has herself set straight. There's no way that she finds her old rival, Hiccup Haddock, attractive. There's no way that she sees him as a friend. No. She's going to graduate. She's not one for death.
When Hiccup is suddenly promoted to Wingleader after the previous one is cooked by his own dragon's flames, he finds himself in a strange world of leadership. It certainly doesn't help that his old rival Astrid, is here, and that she keeps finding herself in unexplainable danger.
These two are thrown together again and again as they slowly find out that everyone hides something within the walls of Basgiath. And that the biggest secrets held by the most important people might just kill them all...