"He always describes his characters' voices and their physique so brilliantly. As people have said, they are cartoons, caricatures. They're grotesques really"

This quote by Simon Callow speaks to the luster of the author he is referring to. He is highlighting the author's capability to create vibrant and special characters through their physical descriptions and the method they speak. He is stating that these characters are not practical, but rather overstated and practically cartoon-like. They are caricatures and grotesques, which indicates they are overstated and distorted variations of truth. This quote speaks with the author's ability in developing characters that are so brilliant and memorable that they nearly appear to come to life. It is a testament to the author's creativity and skill in creating characters that are so special and unforgettable.