Lionheart's History
Early Life
Kelsey Leigh was a single mother with two young children who lived in Ipswich in East Anglia, England. She was a schoolteacher who taught English literature and history. Back when she was married, thugs invaded her home. One of them attempted to rape her: she fought back, hurting him somehow and he cut her face with a broken bottle in revenge, scarring her permanently. Meanwhile, her husband, Richard, was too paralyzed with fear to help her. His guilt over that incident led to the dissolution of their marriage.
Becoming Captain Britain
One fateful day, her family found themselves on the front line of a battle between the Avengers and the Wrecking Crew. Thunderball rendered Captain America unconscious and Kelsey selflessly put herself between the fallen Captain and Wasp, using the downed Captain's shield. While the shield was indestructible, Kelsey wasn't, and the shock from the blows inflicted terrible injuries on her; she died en route to receiving medical attention.
Kelsey awoke to find herself in a ring of standing stones, where she was met by a vision of Brian Braddock (the former Captain Britain), currently the ruler of Otherworld, and his wife, the elemental shapeshifter Meggan. To save Britain from the evil Morgan Le Fay, he passed the mantle of Captain Britain to Kelsey. Her heroic act of bravery earned her a second chance to live and to defend her home. Given the choice between the Sword of Might and the Amulet of Right, Kelsey, desperate to see her children again, and not seeing how a necklace could defend anything, chose the sword, the path of violence. Instantly, she was transformed into the new Captain Britain, only to discover that her decision meant that if she ever revealed who she was to her children, it would cost them their lives.
The new Captain Britain returned to Earth, where she helped the Avengers defeat Morgan and her cronies, proving herself to be far more ruthless in battle than her predecessor, and apparently killing Thunderball when she impaled him on her blade. With her children in the Avengers' care, Kelsey accepted an offer to join the team, so that even if she could not be reunited with her children, she could remain near them.
Kelsey remained a member of the Avengers until the events of Avengers Disassembled. When She-Hulk went berserk after an attack by Ultron robots, Kelsey stepped up, once again putting herself in the path of danger to rescue the fallen Captain America. She-Hulk knocked her unconscious, and she spent the remainder of the unfolding events in the hospital, her status critical. Kelsey did fully recover, but left the disbanding Avengers and returned home to England.
Becoming Lionheart
Soon afterward, the original Captain Britain returned to Earth and reclaimed the name. Going by the codename of Lionheart, Kelsey remained an active superhero in England but eventually came seeking revenge and blaming Captain Britain for what had happened to her, for not warning her of the consequences of choosing the Sword of Might and for losing her children.
Lionheart was manipulated by Albion, a supervillain who also dislikes Captain Britain. Lionheart, though struggling to fight her conscience, would have killed Courtney Ross, the Captain's former girlfriend, if it was not for the arrival of Juggernaut and Nocturne. After a fight between Albion and Captain Britain; Lionheart and Albion fled.
Later, Lionheart betrayed Albion, whose group was defeated by the New Excalibur team. It was then revealed by Pete Wisdom that when Kelsey died, she was "caught up in a rather sticky situation", but "the Crown needed her", and she had been on a "secret mission" since then. Because they felt it was safer to keep Kelsey's identity hidden from both her family and the public, for her family's safety, they waited until the end of the mission to reveal the truth to Kelsey's mother and children.
