First lieutenant

First Lieutenant is a junior commissioned officer of the UNSC Marine Corps, equal in rank to Lieutenant, Junior Grade in the UNSC Navy.

A First Lieutenant usually leads specialized platoons, or may be the Executive Officer (second in command) of a Company-sized unit (110 to 140 personnel).

A Second Lieutenant usually receives a promotion to First Lieutenant after 18 to 24 months service.

In informal settings, First Lieutenants are referred to simply as "Lieutenant".