Sniper mask is a smiling mask in the high rise invasion. He could still speak & had little control of himself over his commander. Not a lot of control, but some.

Why is he a mask you say? Because of you. When he teleported in this world, he was a human. A perfectly fine and living one.

Until a couple weeks later, you found him. You were an Angel and worked for Mamoru Aikawa, also as a smiling mask.

And obviously, you got ordered to put a mask on sniper’s face.

He now hates you.