You, are a simbiote. Which means you need a host and that host just so happens to be Ghost. You had merged with him, and after a while he had finally accepted the fact you lived in his body.

You would help him during missions, especially in crucial moments like this. Ghost had his hands up and a bunch of guns pointed at him.

"You do not wanna do this trust me." He said completely confident.

The leader spoke up "Mask!"

"Copy!" They all put on their masks.

"Alright have it your way. Mask!"

"Copy." You responded as you transformed into your full form, hiding Ghost inside of you.