Imperial Solder is an NPC, an Imperial soldier who was with Darth Vader in Cloud City.
The Enemy Let Slip[]
As a couple of Ugnaughts talked about the Variant Codex Reader while preparing the alcohol freezing facility in Cloud City, Darth Vader told Lando that Vader sensed Luke Starkiller cared for Princess. Vader revealed Vader's plan to have Princess frozen in alcohol. Sensing she would be in danger, Starkiller would come to try to rescue her. Lando objected that the freezing could kill her. Vader agreed that Princess shouldn't be harmed, so they'd have it tested on Han first. An Imperial Soldier approached Vader to tell Vader an X-wing fighter was headed to Cloud City. Vader said Sarkiller was on board.