Sword Art Online: Alicization

Eugeo and Kirito face off against an Integrity Knight named Eldrie after they run away from prison. Kirito and Eldrie start fighting but soon it is revealed that Eldrie has a Divine Weapon. Eugeo remembers who Eldrie really is; when Eugeo starts listing off different things the Knight has done, Eldrie starts screaming, saying that he has no such recollection of those memories. He then falls to the ground, and an unknown purple crystal emerges from his forehead. When Eugeo tells Eldrie his mother's name, he starts crying, then another Integrity Knight comes and attacks Kirito and Eugeo. They both run towards a dead end, where a warp gate appears in front of them, taking them to a grand library. The woman who teleported them turns out to be the Cardinal System of that world, and knows that Kirito is from the real world. She then goes on to explain the history of the VR world and who developed and created the Taboo Index.