SpoilerShe is the future wife of Hashida Itaru, with whom she will have a daughter named Suzuha. In the Alpha world line, her husband invents a time machine in 2036, which Suzuha uses to travel back in time. SpoilerIn the manga "Boukan no Rebellion", it's revealed that Yuki is killed by Tennouji Nae, moments before Suzuha uses the time machine.
In the anime (Steins;Gate 0), however, Yuki dies saving Suzuha (World Line: Beta)