Father: I had a courser watching the vault exit for years. As soon as it started cycling, it teleported back and I had the caniform unit deployed to the Red Rocket near your old home. When our people swept the house after I was removed from the vault, they found an empty dog bowl and recovered some remarkably viable DNA. When I discovered them in the archives, I realized an Alastian would be a creature you would be likely to trust readily. I had hoped to reconstruct my birth mother and place it in the cryopod and dispose of the carcass, but the records indicated you may have witnessed her termination, and if that were true, the risk of raising your suspicions would have been too great.
Teleporting the caniform unit to Diamond City when you entered Kellogg's residence was risky, but for some reason you didn't seem at all surprised when it appeared outside, ready to track our agent. Kellogg was supposed to subdue you and bring you in for study at that point, but he was always unpredictable. The Courser Program had made him effectively obsolete by that point, so his destruction was only a minor setback.
Thank you for taking the caniform with you to the agitators' headquarters, by the way. Our strike team should be mopping up there about this time. We shall replace the most prominent members with customized Coursers and maintain the facade of their operation, bringing the malfunctioning synths right back to us with far less collateral damage.
Nate: German Shepherd, you freaking monster!