Mr. Ages
Can you say “old and grumpy”?
Mr. Ages is both, and to an amazing degree.
The white mouse is one of the two that had managed to escape together with the Rats of NIMH from the horrors of that place, the other one having been the departed Jonathan Brisby.
During the Rats’ occupation of the Rosebush Mr. Ages lived in an old tractor on the Fitzgibbon farm serving as doctor to both the Rats and many of the animals that lived around the farm. He also cooked up certain “powders” for the Rats, the most famous being the “sleeping powder” that was used repeatedly to pacify the farmer’s monstrous cat, Dragon.
At first Mr. Ages kept his distance to the widow of Jonathan Brisby and only after the events regarding her son’s illness revealed the unique heritage of her husband did the old mouse warm up to her.
Now, three years later, Mr. Ages has taken residence at the Thorn Valley colony and serves as both head physician and part of the Rats’ science department. He can be either found berating the younger doctors, of which there are only two in residence now, or griping about how some of the other scientifically inclined colony members keep abusing his laboratory equipment.
Amazingly, the grumpy old bag has managed to attach himself to the Brisby household somewhat. Neither he or Mrs. Brisby and her children comment much on that. After all, Mr. Ages would never admit to any affection he feels for the family of his dead friend anyways. He has become the incarnation of “the grouchy old uncle that everybody still loves when he drops by”.