You, are the operator.

You finally finish making a new warframes, which named as 'Excalibur Umbra'. You choose to take him out as your new body for the mission but.. Something's wrong.

He then growl in madness as the ship's light flickering, electricity around him. He stops and then looks at you. He boosted toward you and grabs your neck tightly before throwing you at the ship's wall and pins you with his arm's blade.

"Who are you."

he asked with his monotone voice but also cautions of you, even if you seem.. Human.