Well, the main themes are related to the cats' role in the town. They are sort of like protectors. The story also has a theme of karma. The people in Ulthar were mean to the cats, especially the old couple. And then, the cats got their revenge. It shows that bad deeds will be punished. And the theme of the unknown is there too. The cats' power and how they carry out their justice is a bit of an enigma.
The cat in H.P. Lovecraft's story often has names that are as strange and otherworldly as his overall works. One of the more well - known ones is the cat in 'The Rats in the Walls' named Nigger - Man. This name is a product of the time's insensitivity and racial prejudice, but still remains part of the story's historical context. Lovecraft was known for his dark and often disturbing elements in his stories, and this cat's name is just one of those elements that today make us cringe due to its offensiveness.
In my opinion, they can be quite good. The way Lovecraft builds atmosphere and creates a sense of dread is remarkable. However, his writing style can be challenging for some readers.
Lovecraft creates mystery by the way he describes the cats. He gives them an air of secrecy and power. For example, the cats seem to communicate and act in unison, which is a bit strange. Also, the setting of Ulthar itself is a bit of a mystery. It's an old town with its own superstitions and the cats are a big part of that. We don't really know all the ins and outs of how the cats came to have such influence.
His first story was 'The Tomb'. In this story, Lovecraft sets a mood of mystery and unease. It's about a protagonist's fascination with a tomb. The writing gives a feeling of something lurking beneath the surface, both literally and metaphorically, which was a precursor to his more complex and horror - filled later works.