Thad Jarvis and Thomas are one-off characters who have never interacted in canon. The ship originated from cityoffireflies who was inspired by fanart and memes to conceive of Thad, Thomas, and Bradley as friends. One fanart in particular inspired cityoffireflies' headcanon of Thad having a (possibly unrequited) crush on Thomas, though the fanart had the crush unrequited in the other direction. hot_island_songs added Rebecca to this friend group and joined cityoffireflies in writing fanfiction featuring the ship as well as the larger group of friends.
- Thoad tag on Archive of Our Own