"Unique units" in the free-to-play game C-evo are a handful of units each of which is initially produced by only a single nation. Examples are the Roman ship "Liburna", the Scots "Highlander" (for the Scots tribe that was available for version 1.1.1), and the Japanese "Samurai" (which may have two variants). Players with some computer proficiency may be able to modify files to produce their own unique units that cannot be copied.