Is it permissible to publish and sell books via a website that requires the purchase of a special device to open e-books from it, and is that considered cooperating in sin and aggression?

There is no harm in publishing books on the website, for the fact that the buyer needs a device to open e-books does not prevent it, and the fact that the device may be used for permissible and impermissible things does not forbid its purchase and utilization.