"Imperial Legionnaire" makes you a Legionnaire of the Imperial Legion (it's viewable under the faction list)
A free Legion Armor set is outside the sewer door exited during the tutorial, after Uriel Septim VII is murdered.
Resisting arrest by any guard removes your place among the Imperial Legion.
One of the key differences in Imperial Legionnaire is the conditioning and change of dialogue. Much dialogue (mostly dialogue that have the words "citizen" and "civilian" or other words referring to the player as a civilian) is removed or limited not to function on the player, and much dialogue normally unaccessable are now accessable due to the player being a Legionnaire.
"Imperial Legionnaire" contains no questline, only free armor, edited dialogue and many more allies.
A free Legion Armor set is outside the sewer door exited during the tutorial, after Uriel Septim VII is murdered.
Resisting arrest by any guard removes your place among the Imperial Legion.
One of the key differences in Imperial Legionnaire is the conditioning and change of dialogue. Much dialogue (mostly dialogue that have the words "citizen" and "civilian" or other words referring to the player as a civilian) is removed or limited not to function on the player, and much dialogue normally unaccessable are now accessable due to the player being a Legionnaire.
"Imperial Legionnaire" contains no questline, only free armor, edited dialogue and many more allies.