Owen Lars is a human male moisture farmer on Tatooine, son of Cliegg Lars and step-brother to Anakin Skywalker, who raised Luke with his wife Beru after Obi-Wan Kenobi brought the infant to the homestead. He was introduced in Star Wars: Episode IV A New Hope (1977), played by Phil Brown, and by Joel Edgerton in the prequels and the Obi-Wan Kenobi series.
Not the villain of the first act
He reads, on a first viewing in 1977, as the obstacle: the uncle who will not let the boy go to the Academy. Everything published since has made him the only adult in the story with an accurate risk assessment. He knows whose son Luke is. He knows what happened to the last Skywalker the Jedi took an interest in. His stubbornness is not small-mindedness, it is the correct answer.
What killed him
The Databank puts the Empire's logic plainly: it "would kill its own citizens to retrieve the droids and the secret information they carried." Owen and Beru die in a raid over a pair of droids, and the smoking homestead is the image that finally sends Luke off-world — the exact outcome Owen spent nineteen years preventing.
Where to read him
The Attack of the Clones novelisation covers the awkward, brief meeting with Anakin; the 1976 novelisation of the first film gives the homestead scenes a domestic ordinariness the film sprints past.