Katharine O'Hare (キャサリン・オヘア) is a Witch of the 507th Joint Fighter Wing, originating from Liberion, serving in the Liberion Navy onboard Aircraft Carrier USS Lexington. She earned the nickname "Crasher O'Hare" due to the number of times she has damaged/destroyed Striker Units, regardless of whether it was due to taking fire, mid-flight collisions, encountering engine trouble, or any other unforeseeable accidents or her own mistakes, including failed carrier landing attempts. Nikka Edvardine Katajainen has also earned the nickname "Second coming of O'Hare", given by Eila Ilmatar Juutilainen. While aboard the Lexington, she was contemptuously referred to as 'That Texan country girl' and 'Southern bumpkin'. Also, while she was in Suomus, Katharine used 'Liberion-1' as her callsign.
Originally assigned to the USS Lexington, her balance while flying was made considerably more difficult by her large breasts offsetting balance. She wrecked so many Strikers, that her punishment was three month suspension from flying. During an attempted carrier landing, she crashed and bounced off the deck, landing in the hangar. The result was all eight of the newly issued F4F Wildcat strikers destroyed, and her fellow Witches injured to various degrees. However, she was the only one who managed to come out of that without a single injury.
The Lexington's captain received an order to send his 'best' witch to Sumous as part of the international volunteer request from the former, and wanting to be rid of Katharine, used the order to transfer her as punishment for her latest wreck. She had totaled a count of 63 Striker Units up to his point.
Katharine is a bit of an airhead, often causing trouble by accident. A recurring gag is her inability to perceive countries outside the United States (an example being that she thought Fuso was located next to Florida). Despite these faults, she does try to get along with everyone. Optimistic, bright, cheerful and sociable. She also was incapable of swimming, however, she loves the sea and the sky. She would be fine with anything, and likes cola and doing her nails. Katharine seems to like firing her revolver for greetings, claiming the rounds to be blanks, and dislikes cold weather.
She is most often seen together with Ursula Hartmann.
Together with the toughness of her F2A Striker Unit, Katherine seemingly has the strongest durability in the Suomus Independent Volunteer Squadron.
While she was on the USS Lexington, she was originally issued with the Grumma F4F Wildcat Striker Unit. However, since she was crashing so many of the Strikers, Katherine was given older, but tougher Beerster F2A Buffalo. Which later received an engine swap from R-1820-34 to R-1820-40, giving increased horsepower.
She uses a Browning M2 Heavy Machine Gun in combat, and carries around Colt Single Action Army Revolver. She does like to draw her gun and randomly fire it, claiming the rounds are "blank rounds", but is in fact, live ammunition. During her inaugural meeting with the Misfits Squadron, she pulled out the weapon and fired at the board in the meeting room, claiming the shots to be blank, but had left 5 holes in the board.
- Strike witches: Chii Sanya, cameo in chapter α-4
- Unknown Witches: Secret File - Chapter 14: 'Liberion's Last Stand'
- Her familiar is the Raccoon. However, during the Character Design stages by Shimada Humikane, her familiar was the Abyssinian.
- Katharine is based on the American flying ace Edward Henry “Butch” O’Hare of the U.S. Navy. However, she holds a lot of differences with her archetype: Katharine is from Texas and Edward from St. Louis, Missouri, Katharine's father was a farmer and Edward's was a lawyer, and more for his destroyed planes, Butch was famous for received the Medal of Honor for shooting down five medium bombers attacking the Lexington early in the war, and also helped pioneer night time carrier operations in the U.S. Navy.
- Katharine shares a lot of similarities with Charlotte E. Yeager. Both of them are tall and buxom (and are the same height), originate from Liberion, are related with Striker Units (Katharine has lost a lot of Strikers, and Shirley is a mechanic and has modified and tuned her strikers), both are bright, sociable and optimistic, they are considered beautiful, have a good relationship with the 'little girl' of the squadron (Ursula and Francesca Lucchini, respectively) and are important characters in their respective media.
- Her name is sometimes misspelt as Katherine.
- There were seven girls who were considered her squadmates while she was stationed on the Lexington: Rita, Vivian, Ingrid, Mary, Beth, Sally and Linda. The seven girls were seriously injured and their strikers destroyed from Katharine's failed landing attempt onto Lexington's flight deck.