Dennis's Gran lives in Beanotown with Rasher, Dennis's pet pig.
Her name's Catherine and the reason she's Dennis's Gran is that her son is Dennis's Dad.
When he was a kid, Dennis's Dad was a lot like Dennis, but he's forgotten all that now he's a grown-up. Luckily, Gran remembers everything!
Dennis's gran is the most epic Gran in the world. She thinks kids should have fun ALL THE TIME, and that grown-ups take themselves too seriously.
If she had her way, there'd be less freaking out in the world and more chilling out, hanging out and letting it all out.
This is how cool Gran is: once upon a time, an awesome boy - let's call him Dennis - came home with a pig called Rasher. Dennis wanted to keep Rasher as a pet, to save her from a fate worse than sausages (or exactly as bad as sausages).
Dennis's Mum and Dad thought keeping Rasher would be too much for them - after all, they already had Gnasher tearing up the house - and that the best thing to do was find out who had lost a pig and return Rasher to them.
But when Gran saw how miserable Dennis was about losing Rasher, she said she had plenty room for a pig at he house, so why didn't she look after Rasher?
Now, thanks to Gran, Dennis can go and see Rasher any time he likes.
Gran also has a seriously banging motorbike, which is really fast and loud.