Watto was a Toydarian junk dealer who had his own shop on Tatooine for used parts. He became the owner of the slaves Shmi and Anakin Skywalker after a gambling match, the former who would grow up to become Darth Vader. He quickly found out about Anakin’s aptitude for technology and even had him pod racing.
His one weakness however was his love for gambling, and this is also how he lost Anakin Skywalker to jedi Qui-Gon Jinn after a pod racing match. He did however kept Shmi Skywalker as his slave, something that always haunted Anakin and the thing that made him return back to Tatooine, to free his mother like he had promised. It seemed Watto had already sold her to a moisture farmer for a little extra money. Anakin disappeared angered after this. It was the last time Watto would see either of his former slaves.