Seinen (targeted at adult men) often deals with darker themes, slower burns, and morally ambiguous characters. This is where anime and manga prove they are not "just for kids."
It is the "punk rock" of Shonen. Tatsuki Fujimoto breaks every rule of storytelling. It is violent, weird, horny, and brilliant.
Best for: Mature themes, plot twists, and intensity.
If you are searching for these specific files today, it is important to exercise caution. The "WAP" era of the internet is largely unmaintained. Many sites that once hosted these files are now defunct or have been taken over by malicious actors.