Next day,
Yesterday Sam just spent his time in the library. After coming to Terraria, spending his time in the library became a habit of his. He already knows about the history of this human kingdom.
Same as the Oni Kingdom, previously when the first human awakened The Spiritual energy and was able to make those Monsters and Demons retreat, he also decided to build his own kingdom, and because of this right now as you can see the human King Kingdom was present here.
'Most likely every Kingdom was established beside the danger zone so that the warriors did not have to go to another place to go to the danger zone.'
Sam thought that. He did not know about those other kingdoms but he already guessed that those kingdoms were also established beside the danger zone so that all the Warriors of their Kingdom easily get access to the danger zone.