Once a battle TARDIS serving the Time Lords unwaveringly, Osriardan came by unfortunate circumstance and lost their pilot. Moved by a new sense of grief, they broke out of their programming and fled.

Even on the run, Osri found themselves reluctant to leave Gallifrey. Fortunately, this led to their chance encounter and rescue of Delta. Soon after, their adventures led them throughout time and space, and eventually chance encounters with the Time Lords themselves.