Sometimes at night

Sometimes at night, I drift from half asleep to half awake. My eyes open ever so slightly, and I catch glimpses of the chair. 

During the day, there's nobody there. But at night, she sits there. 

She keeps my dreams safe. She sits in the chair, and with rapier reflex and steel cause of strength, she protects me in slumber. 

I've seen her before, but I don't know where

But she keeps me real as she sits in that chair

I've kept my composure to almost no end

And I have her to thank; she is my heart's friend