Kubrick was Adam Jensen's and Megan Reed's dog. After the terrorist attack on Sarif HQ, Sarif employee Diane Gonzales took the dog but could not care for him. At a point when it became doubtful that Jensen would wake up, Gonzales had the dog put down. The email she sent to Jensen, titled "RE: your dog", reads,
"Adam... i'm so sorry.
When megan died nobody knew what to do with Kubrick, so I took him in.
But I couldn't keep him, and nobody knew if you'd wake up, so...didn't know what else to do.
I'm really sorry. He was a sweet dog.
Diane".