R5-D4 or Red (who Luke calls) is an astromech droid. He was once in the possession of Jawas, and then sold to Owen Lars. R2-D2 was given orders by Princess Leia to get to Obi-Wan Kenobi under any means necessary,so he wrecked R5's motivater so he could get off the sandcrawler and find Obi-Wan instead of R5 getting off. After R5 malfunctioned, he was replaced by R2-D2 under the suggestion of C-3PO. The droid was never seen after that.