The Impact of God Slaying Weapons
The dark god, Nyarlathotep, does not care if the subjects it created are easily dealt with. It is only buying time for its power to fully manifest inside of the imperial capital. It also has three layers of defense barriers erected which is why it does not fear being attacked by surprise.
Like all gods told in stories and legend, it believes in itself as the most superior or else its authority as a god will be questioned. The gods and goddesses in ancient mythology are not prideful or overconfident because they believe to be but because they need to be.
Gods and goddesses in myths and legends are only what they believe themselves to be as they self-actualize. If a god or goddess believes that they are the same as normal people, then they will become powerless and normal.