Lilly Frobisher
From Tardis Wiki, the free Doctor Who reference
Lily Frobisher was the daughter of John and Anna Frobisher and the older sister of Holly Frobisher. Like all other Human children, Lily was taken over by the 456 to convey messages to Earth. (TW: Children of Earth: Day One) After their father found out that Brian Green, the Prime Minister, was planning to take Lily and Holly to the 456, he killed his family, Lily included, before shooting himself. (TW: Children of Earth: Day Five)