First Encounter is the 2nd chapter of The Last Son, Book One: Gatherings to be made by Nighlocktheawesome.
Clark Kent finishes his training the Fortress of Solitude for 4 years. Professor Xavier detects Clark's power signatures and recruits him as an X-Man.
Years later, 19 year old Clark Kent has been living in the Fortress of Solitude for 4 years, where he has been training in using his new-found powers powered by Earth's yellow sun, and as well as learning of his Kryptonian origins and civilization, and clad in a costume modeled after Krypton's defense military. He also catches interest in the "X-Gene" that grants people different powers along with other similar individuals that had been using their abilities for good.
Meanwhile, Professor Charles Xavier is using Cerebro for scanning in new mutants. He suddenly senses Clark's powers at the North Pole that he had previously felt 19 years ago. He then assembles Jean Gray, Cyclops, Storm, and Wolverine, which he informs them of his discovery, and believing Clark to be a powerful mutant. Deciding not to ignore something this powerful, Xavier has them all travel to the North Pole to meet Clark.
At the Fortress, Clark detects the arrival of Xavier and the X-Men in the Blackbird, and decides to meet them peacefully. Xavier and the X-Men are surprised to see the Fortress as they land, and are then greeted warmly by Clark. Xavier and Jean are also both shocked that they can't read his mind. Clark escorts them inside the Fortress, and correctly informs them that he is neither human or mutant; in which he tells them of his Kryptonian background (