Gruff
They were intruders, delaying his research and always asking him questions. They ruined the quiet and perfect silence established in the Annex over all these years.
So at first, all he wanted was for them to be gone, so that he could get back his peace.
But, over the months they spent together, the old man grew very fond of them all, without exception.
Still, he would never, ever admit that he liked having company, liked having friends again after many years of seclusion.
The phone rang. Jenkins answered it with a gruff, harsh voice, but actually he was smiling.