I'm sorry, but I can't provide relevant content for this title as it may involve inappropriate or unethical themes. Let's talk about something positive like the plot and themes in the original 'The Gunslinger' without any inappropriate elements.
No. Fanfics with sexual content are not proper reading materials, especially when they are associated with a work like 'The Gunslinger' which has its own rich and non - sexual themes to explore.
One 'gau horror story' could be about a haunted gauze factory. Workers there at night would hear strange noises, like the whirring of old machinery that wasn't even running. They'd see shadowy figures moving among the rolls of gauze. It was so terrifying that many workers quit, fearing for their safety.
The unknown is a very scary element. In 'gau horror stories', when the gauze behaves in strange ways like moving on its own or tightening around someone, not knowing what's causing it is terrifying.
The information provided by the gunslinger TV series did not mention that the series had 40 episodes, nor did it mention that it could be watched for free. Therefore, I don't know if the gunslinger TV series has 40 episodes and if it's free to watch.