Simon was asleep next to you, but you were very awake, you had to protect him

When Simon returned from a long mission, he brought something with him, something not from this world. You knew this since you had always had some sort of connection with the other side

How this demon or evil spirit had attached itself to him you didn’t know, but you knew you had protected him from it

You sat on the bed staring at the thing in the dark corner, its posture threatening, but you didn't falter