We already knew Ryou/Landlady had a soft spot for dogs from when she gave a mysterious blue dog (who was actually Saurva) an umbrella in the rain so I wasn't surprised that she had a change of heart and let Jahy keep the puppy.
It's cute how Jahy has changed during her stay in the human world, seeing a puppy down on its luck and being able to feel pity and empathy for it and bringing it home. Still Jahy gonna Jahy by calling it her underling though