Legio IX Hispana
Iberian Legionaries fighting in Britain’s cold and gray wasteland.
There were 2 “walls” in Britain if you care.
Everybody knows about Hadrian’s Wall, but hardly anybody knows about the Antonine Wall (Vallum Antonini) built a few decades later. Not much of it exists anymore.
Rosemary Sutcliffe's "The Eagle of the Ninth" is the source of the modern myth that a Roman legion was annihilated in Caledonia (not Scotland, the ancestors of the Scots were peeing their kilts in fear in Ireland for a century after the Romans left Britain). The loss of the Ninth in Caledonia just didn't happen. Roman conquest of Caledonia was never finished because A) there wasn't anything of much value in the whole territory and B) because there was seldom any threat at all from the Pictish population.