Catherine is a character from Fire Emblem: Three Houses and Fire Emblem Warriors: Three Hopes. She is a Knight of Seiros, and she can train Byleth in the Swords and Brawling skills. She possesses a Major Crest of Charon. She is 27 years old at the start of the game. As one of the most powerful Knights of Seiros, Catherine is extremely loyal and a devout believer in the Church and Rhea, the latter being an attachment. This is due to Rhea taking her in during her greatest time of need, and as such, feels that it must be repaid in full. Her devotion to the Church is extreme that in a conversation with Shamir, if someone spoke of heresy and she didn't know them, she'd cut them down on the spot. Her loyalty to Rhea is also unwavering, following her to the very end, despite the apparent insanity she falls into during the Crimson Flower route. Aside from her role as Rhea's bodyguard, she is a fierce warrior with a reputation to back up her skills, being known as Thunder Catherine. While many knights idolize her, she feels that she is not worthy of such praise. She gets along well with her fellow knights Alois and Shamir, especially with the latter despite their vastly different personalities, due to having fought many battles together. She is also willing to help others, such as telling Ingrid to resort to dirty tactics as a last resort, as war can be quite dirty and not what the stories make it out to be. She also helps Ashe find closure in the role she played in Christophe and Lonato's deaths. She has an innate sense of identifying people with crests with a single glance. She could correctly pick up on Lysithea's crest secret and knows that she has a Crest of Charon like she does. The two can form a bond akin to sisters if their support is pursued.