Irene Reppler is an elderly, but tough, schoolteacher and the film replacement for Hilda Reppler.
Irene is a schoolteacher and is among the patrons trapped in the Grocery Store when the Mist appears and engulfs the town outside. She constantly proves herself to be one of the most capable members of David's group.
She is part of the expedition to King's Pharmacy on the second day. As Mrs. Carmody preaches insanely to her followers, Irene, tired of Mrs. Carmody's fanaticism, stones her with a can, sending her into a rage. When the group is attacked by Gray Widowers in the pharmacy and one confronts Irene, she easily defeats it by very calmly spraying ignited bug spray at it, and then escapes back to the market with the others.
The next day, Irene helps protect Billy and Amanda from Mrs. Carmody's followers until Mrs. Carmody is killed, then escapes to David's Land Cruiser. She and the others who make it, drive south through the Mist until the Land Cruiser finally runs out of fuel. When it does, Irene and the others enter a suicide pact and are duly shot by David to spare them a more violent death from the creatures.
Their deaths are apparently in vain, however, as a military convoy arrives moments later.
Despite her elderly age, Irene is shown to be a very tough and capable woman. She also hates Mrs. Carmody and is not afraid to show it, as evidenced by her stoning and yelling afterwards.
Irene deeply hated Mrs. Carmody and was very open about it, even in full view of Mrs. Carmody's followers and even when Mrs. Carmody was becoming more and more homicidal. When Mrs. Carmody began preaching before the pharmacy expedition, Irene stoned Mrs. Carmody with cans of peas to get her to shut up, and then rubbed it in by reminding her that stoning was not regarded negatively in the Bible.
Irene called Jim an underachiever from when she taught him at school. Jim also appeared to somewhat respect her, but the respect was replaced by hatred after he became a follower. He tried to kill her alongside David's group under Mrs. Carmody's orders, but was unsuccessful.
Irene got along very well with both David and Billy. She watched Billy whenever Amanda, Sally, or Hattie were not around and helped protect him from Mrs. Carmody's followers when they tried to murder him.
Amanda and Irene seemed to be close friends due to them being co-workers.
When Hattie became terrified for her husband, Irene warmly tried to comfort her.