Time Lord soldier 1 (The Last Day) for better disambiguation with Time Lord soldier 2 (The Last Day)
Talk about it here.
He helped a newly recruited soldier on his first day on the front line at Arcadia during the Last Great Time War. He and the new recruit scanned the skies of Arcadia as a Dalek fleet broke through the sky trenches and invaded Arcadia. (TV: The Last Day)
Carrying a gun and a bazooka, he sent a Priority Omega message for the High Council reporting that Arcadia had fallen. There he saw the Doctor's TARDIS and was met by the War Doctor, who asked to borrow his gun. Taking the soldier's gun, the Doctor proceeded to blast the message "NO MORE" into a wall before flying his TARDIS into a squad of Daleks. A damaged Dalek remaining told the soldier to explain the meaning of those words, the soldier answered by using his bazooka to finish the Dalek off. (TV: The Day of the Doctor)