So, basically, the whole gates/hunters/Yada Yada mess, began because in another world, there is a war, between two factions, the Monarchs, and the "Angels" you see in the previous chapter.
The war eventually was moved to Earth, with the Monarchs, the bad guys, so to speak, open the gates in order to invade the world, and the Angels instead give power to humans, hence the creation of the Hunters and their awakening.
In the first chapters Jinwoo finds a double dungeon with his guild, they enter and in the end, the only one left inside alive was Jinwoo. For this fear he obtains the power of the player and the possibility to level up. So he does that, gaining power and eventually becoming the S rank we know now.
After he surpasses level 100, he obtains a key that brings him in the same double dungeon he first obtained the "Player" power, when he meets the statues again, only, this time, he realizes that the only statue that doesn't move, aka the one with the instructions, is actually the master of the dungeon.
After level 100 he obtained a power called the "Black Heart", literally a second heart that in theory, was supposed to be a power boost. It actually isn't.
Battling the Statue (the one with the instructions), he asks who he is, and here they probably lost not only you, but several readers, mostly because of mistakes with the translation, in the novel it isn't nearly as this incomprehensible.
The statue answers that his name is "The Architect", and he is the one that devised the player system, one of his abilities is to predict things, as demonstrated in the last chapter.
Now, this is the real spoiler part.
You see, the whole player thing is bullshit. Monarchs, in order to invade earth, need a host, the problem is that not anyone can become one. Moreover, the Monarch of Death, the one Jinwoo gets his powers from, is the most powerful. So in order to obtain a vessel able to withstand the power of the Death's Monarch, they needed to create one.
So the Monarch of Death, named Ashborn (in the novel, we will see how they will call him in the Manga), teamed with the Architect and they togheter created the Player System that will be later obtained by Jinwoo, in order to train a person to become stronger enough to be the vessel for Asborn.
So, what should have happened in these chapters, is that Jinwoo's consciousness should have been replaced with Ashborn's, but it wasn't, and that's why the Architect is surprised.
The reason Jinwoo was called again in the double dungeon was to awaken Ashborn, "problem" is (in the Architect's point of view), instead, Jinwoo is still the one that is owning the body.