In her teenage years (accounting for Millennial Kingdom longevity calculations, this means her 70s to her 90s of a projected 1000 year lifespan), she is a worker at Children of the Tribulation. One of her friends is Cendrillon Jospin. Mercy is distraught when Cendrillon latter dies, and takes it as a warning to examine her own conscience. After getting saved, she encourages their mutual friend Sergei to accept Jesus.
During this time, Mercy is also friends with Matthew, a Glorified.
Later in life, Mercy and Sergei fall in love, and get married in a reconstructed Orthodox church.
She continues her work at COT and witnesses the emergence of Revenants.
At the end of the Millennial Kingdom, she is welcomed into Heaven by God at the White Throne Judgment.