Oh right, I always forget to ask. Whatever happened to yellow’s mum? Is there lore I’m missing out on, or is it a matter of “just don’t think too much about it”

Nothing happened to her, really. She hit young Roy’s life like a hit-and-run with a 9 month delay. Started her own family, somewhere, years later. Probably doesn’t even remember Yellow and Roy exist anymore, to be honest, and if she does, she never did bother to contact either of them. And really, that’s for the better, for everyone involved. She has her husband now, Roy’s got his... 

To say they weren’t ready for a child is an understatement. They barely even knew each other, all things considered, so you can see how this came as quite a shock to the both of them. I mean, Roy didn’t even think he was ever going to be a father (and now look at him!) though don’t get me wrong, he wanted to be. Just, you know, not like this. But it was a responsibility one of them was going to have to accept, and it wasn’t her. And then she moved out of town not too long after, and hasn’t been heard from since. But at least Yellow’s in good hands.