Twilight was in the front once, at the beginning of the war. Her, a simple librarian from canterlot wanted to protect her sister in law like her brother already did.
She almost died on duty. Unable to fight, she was sent home and helped organise what happened behind.
Her brother came to see her and Cadance, one last time. Cadence became pregnant and Twilight tried her best to keep her safe, far from the war as possible.
Until war took at both mares had most precious.
When Princess Twilight came, Twilight was with her family.
When Princess Twilight came, Twilight was visiting her brother.
I just loved the last Episode from S5! Especially the Sombra time!
I just love tragic stories. One thing I've seen after the episode was Brony asking where was Twilight in each alternate universe.
So here is my version of Sombra universe.