1:Origins

Echo Shirogane was the sister of Takashi 'Shiro' Shirogane, prisoner of the Galra.

Instead of Shiro fighting in the Gladiator arena it was Echo. She became Champion and escaped with him back to earth. When the two are found by Keith, Lance, Hunk and Pidge they embark on a journey through the universe.

(The summary is really bad I suggest just reading the first chapter or something.)

ALL CREDIT GOES TO THE CREATORS OF VOLTRON LEGENDARY DEFENDER EXCEPT FOR MY OC AND MY IDEAs