Mamoru, along with everyone else, is revived in episode 200 and is reunited with Usagi.
What episode does Mamoru leave for America?
Sailor Moon Sailor Stars episode 173 – Mamoru leaves for America | Sailor Moon News.
Why did Mamoru leave America?
7 Mamoru Leaves To Go To America
Mamoru graduates from high school and decides to go to college. ... He's not really seen again in the manga after that, aside from an evil Tuxedo Mask appearing during the climactic battle with Sailor Galaxia, and he communicates with Usagi exclusively by airmailing her photos of the sky.