Mr. Ages
Mr. Ages is a mouse who had the same injections as the rats. He and Jonathan are the only mice to escape with the rats and live with them. He is a doctor who makes Dragon's powder which he broke his leg trying to do. He also made the medicine for Timothy. He told Brutus to step aside to let Mrs. Frisby in and showed her to the library. Mr. Ages stayed near the rosebush and revived the unconscious Brutus and says the last words of the book (not including the Epilogue).