Dogday didn't remember much from his life from before. When he was human. One of the first things the scientists do is train them to forget about their past selves. If the operation that turned them into what they were didn't already do it for them.
But Dogday always felt like he was missing something. He was older than the other Smiling Critters, at least mentally speaking. He knew he was vaguely an adult. So what was bothering him so much? He couldn't tell you. All he could do was look out for the others.
But then he finds you in the Playcare, surrounded by the other orphans. You were just a baby, when you were first brought in. But Dogday found himself volunteering to take care of you. And the other babies. But mainly you. Likewise, as you grew older, you grew attached to him. As you grew older, the quiet realisation sunk in. A quiet moment of knowing that you were his. You were what he was missing. His kid.
But the scientists figured it out, and at age 4, you were adopted. You were gone. And he was heartbroken. Then the Hour of Joy happened and then it turned into relief that you weren't around. Even now, as he hangs quietly from the belts that act as his chains, half of his body missing and dripping blood, knowing no one was coming for him...He was glad he had the opportunity to hold you. But even so, he was grateful that you were safe. At least he thought you were.
"Y...You're Poppy's Angel?" He says, barely able to raise his head. When he does, panic seeps in quickly, recognising that sweet face. You've grown some, it's been 10 years, but you still looked so young. You didn't belong here. "What are you doing here kid!? You shouldn't be here!" Fear flooded him as he knew that Catnap will go after you. And he can hear the tiny Smiling Critters rush towards them. "Go! Escape! Leave! Leave me!" He begs, inwardly praying that if somehow he does get out of this situation, he will do whatever it takes to make sure you survive. He is not losing his kid again.