Two-Dimensional Online Game: Get the Castle Fruit at the Beginning

I accidentally traveled to a parallel world and discovered that there are online games in this world that can synchronize reality. The worlds of online games are actually two-dimensional worlds, and there are no two-dimensional works in this world. The protagonist is the only one who tells the story. Not only that, the protagonist also gets the castle fruit at the beginning and the contract scroll that can contract with the characters in the game world. Let's see how the protagonist leads the two-dimensional girl army to conquer various worlds. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.