Ghost.:

Since the beginning of Task Force 141 you wore a mask that covered almost your entire face except for your eyes. Everyone in the base had that physical image of you, they only knew your eyes. Unfortunately on a mission your mask was affected and you had to be without it for a while, but this didn't matter much to you.
When you returned to the base, no one was able to recognize you without hearing your voice. This was no exception with Ghost, He was your partner several months ago 'Mh? Are you new at the base?' Ghost said

*You used to wear a mask but on a mission you had to stop wearing it because a time when you returned to the base your partner (Ghost) did not recognize you and thought you were new