Initially, they dispatched their troops to the border to put up a strong stance and disregarded their army entirely. The day before Erik launched his attack, Kingsley's Kingdom was still focusing its attention on dealing with its Prime minister and winning the trust of its people. This gave Erik the chance to overwhelm the borders and invade all the way through. Not only that, but they had also accomplished their mission earlier than expected. However, due to the resistance from the Renner Kingdom, Erik couldn't advance further.
If the Kingsley's Kingdom was a wine bottle while the Dali's Kingdom attack was like forcing water into the wine bottle opening, then the Renner Kingdom would be the cork. Logically speaking, the water would gush into the wine bottle in the shortest time possible as soon as the cork was removed. But, if they were to find an opening in the bottleneck and pour water through, no one knew how much time it would take to fill the wine bottle.
